diff --git a/NAMESPACE b/NAMESPACE
index 4b4e63b..a18c887 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -47,6 +47,7 @@ exportMethods("totals<-")
 exportMethods(aggregate)
 exportMethods(all_assigned)
 exportMethods(any_assigned)
+exportMethods(as.data.frame)
 exportMethods(as_amounts)
 exportMethods(as_composition)
 exportMethods(as_graph)
diff --git a/R/AllGenerics.R b/R/AllGenerics.R
index 3551377..3dbf389 100644
--- a/R/AllGenerics.R
+++ b/R/AllGenerics.R
@@ -183,8 +183,6 @@ setGeneric(
 )
 
 # Extract ======================================================================
-
-
 ## Subset ----------------------------------------------------------------------
 #' Extract or Replace Parts of an Object
 #'
@@ -272,6 +270,26 @@ setGeneric(
   def = function(object, value) standardGeneric("totals<-")
 )
 
+#' Coerce to a Data Frame
+#'
+#' @param x An \R object (typically, a [`CompositionMatrix-class`] object).
+#' @param row.names A [`character`] vector giving the row names for the data
+#'  frame, or `NULL`.
+#' @param optional A [`logical`] scalar: should the names of the variables in
+#'  the data frame be checked?
+#' @param group_var A [`character`] string specifying the name of the column to
+#'  create for group attribution.
+#' @param ... Currently not used.
+#' @return
+#'  A [`data.frame`].
+#' @example inst/examples/ex-coerce.R
+#' @author N. Frerebeau
+#' @docType methods
+#' @family mutators
+#' @name as.data.frame
+#' @rdname as.data.frame
+NULL
+
 #' Matrix Transpose
 #'
 #' @param x A [`CompositionMatrix-class`] object.
diff --git a/R/coerce.R b/R/coerce.R
index 24683d7..2c7d1c3 100644
--- a/R/coerce.R
+++ b/R/coerce.R
@@ -93,40 +93,74 @@ setMethod(
 # To data.frame ================================================================
 #' @method as.data.frame CompositionMatrix
 #' @export
-as.data.frame.CompositionMatrix <- function(x, ...) {
-  as.data.frame(methods::as(x, "matrix"), row.names = rownames(x))
+as.data.frame.CompositionMatrix <- function(x, row.names = rownames(x),
+                                            optional = FALSE, ...) {
+  as.data.frame(methods::as(x, "matrix"), row.names = row.names, optional = optional)
 }
 
+#' @export
+#' @rdname as.data.frame
+#' @aliases as.data.frame,CompositionMatrix-method
+setMethod("as.data.frame", "CompositionMatrix", as.data.frame.CompositionMatrix)
+
 #' @method as.data.frame GroupedComposition
 #' @export
-as.data.frame.GroupedComposition <- function(x, ..., group_var = ".group") {
+as.data.frame.GroupedComposition <- function(x, row.names = rownames(x),
+                                             optional = FALSE, ...,
+                                             group_var = ".group") {
   z <- data.frame(
     methods::as(x, "matrix"),
-    row.names = rownames(x)
+    row.names = row.names,
+    check.names = !optional
   )
   z[[group_var]] <- group_names(x)
   z
 }
 
+#' @export
+#' @rdname as.data.frame
+#' @aliases as.data.frame,GroupedComposition-method
+setMethod("as.data.frame", "GroupedComposition", as.data.frame.GroupedComposition)
+
 #' @method as.data.frame LogRatio
 #' @export
-as.data.frame.LogRatio <- function(x, ...) {
-  as.data.frame(methods::as(x, "matrix"), row.names = rownames(x))
+as.data.frame.LogRatio <- function(x, row.names = rownames(x),
+                                   optional = FALSE, ...) {
+  as.data.frame(methods::as(x, "matrix"), row.names = row.names, optional = optional)
 }
 
+#' @export
+#' @rdname as.data.frame
+#' @aliases as.data.frame,LogRatio-method
+setMethod("as.data.frame", "LogRatio", as.data.frame.LogRatio)
+
 #' @method as.data.frame GroupedLogRatio
 #' @export
-as.data.frame.GroupedLogRatio <- function(x, ..., group_var = ".group") {
+as.data.frame.GroupedLogRatio <- function(x, row.names = rownames(x),
+                                          optional = FALSE, ...,
+                                          group_var = ".group") {
   z <- data.frame(
     methods::as(x, "matrix"),
-    row.names = rownames(x)
+    row.names = row.names,
+    check.names = !optional
   )
   z[[group_var]] <- group_names(x)
   z
 }
 
+#' @export
+#' @rdname as.data.frame
+#' @aliases as.data.frame,GroupedLogRatio-method
+setMethod("as.data.frame", "GroupedLogRatio", as.data.frame.GroupedLogRatio)
+
 #' @method as.data.frame OutlierIndex
 #' @export
-as.data.frame.OutlierIndex <- function(x, ...) {
-  as.data.frame(x@standard, row.names = rownames(x))
+as.data.frame.OutlierIndex <- function(x, row.names = rownames(x),
+                                       optional = FALSE, ...) {
+  as.data.frame(x@standard, row.names = row.names, optional = optional)
 }
+
+#' @export
+#' @rdname as.data.frame
+#' @aliases as.data.frame,OutlierIndex-method
+setMethod("as.data.frame", "OutlierIndex", as.data.frame.OutlierIndex)
diff --git a/inst/examples/ex-coerce.R b/inst/examples/ex-coerce.R
index c5c4f45..5a8a64d 100644
--- a/inst/examples/ex-coerce.R
+++ b/inst/examples/ex-coerce.R
@@ -11,5 +11,5 @@ totals(B)
 A2 <- as_amounts(B)
 
 ## Coerce to a data.frame
-X <- data.frame(B)
+X <- as.data.frame(B)
 head(X)
diff --git a/man/as.data.frame.Rd b/man/as.data.frame.Rd
new file mode 100644
index 0000000..08cabaa
--- /dev/null
+++ b/man/as.data.frame.Rd
@@ -0,0 +1,80 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/AllGenerics.R, R/coerce.R
+\docType{methods}
+\name{as.data.frame}
+\alias{as.data.frame}
+\alias{as.data.frame,CompositionMatrix-method}
+\alias{as.data.frame,GroupedComposition-method}
+\alias{as.data.frame,LogRatio-method}
+\alias{as.data.frame,GroupedLogRatio-method}
+\alias{as.data.frame,OutlierIndex-method}
+\title{Coerce to a Data Frame}
+\usage{
+\S4method{as.data.frame}{CompositionMatrix}(x, row.names = rownames(x), optional = FALSE, ...)
+
+\S4method{as.data.frame}{GroupedComposition}(
+  x,
+  row.names = rownames(x),
+  optional = FALSE,
+  ...,
+  group_var = ".group"
+)
+
+\S4method{as.data.frame}{LogRatio}(x, row.names = rownames(x), optional = FALSE, ...)
+
+\S4method{as.data.frame}{GroupedLogRatio}(
+  x,
+  row.names = rownames(x),
+  optional = FALSE,
+  ...,
+  group_var = ".group"
+)
+
+\S4method{as.data.frame}{OutlierIndex}(x, row.names = rownames(x), optional = FALSE, ...)
+}
+\arguments{
+\item{x}{An \R object (typically, a \code{\linkS4class{CompositionMatrix}} object).}
+
+\item{row.names}{A \code{\link{character}} vector giving the row names for the data
+frame, or \code{NULL}.}
+
+\item{optional}{A \code{\link{logical}} scalar: should the names of the variables in
+the data frame be checked?}
+
+\item{...}{Currently not used.}
+
+\item{group_var}{A \code{\link{character}} string specifying the name of the column to
+create for group attribution.}
+}
+\value{
+A \code{\link{data.frame}}.
+}
+\description{
+Coerce to a Data Frame
+}
+\examples{
+## Create a count matrix
+A1 <- matrix(data = sample(1:100, 100, TRUE), nrow = 20)
+
+## Coerce to compositions
+B <- as_composition(A1)
+
+## Row sums are internally stored before coercing to relative frequencies
+totals(B)
+
+## This allows to restore the source data
+A2 <- as_amounts(B)
+
+## Coerce to a data.frame
+X <- as.data.frame(B)
+head(X)
+}
+\seealso{
+Other mutators: 
+\code{\link{mutators}},
+\code{\link{totals}()}
+}
+\author{
+N. Frerebeau
+}
+\concept{mutators}
diff --git a/man/as_amounts.Rd b/man/as_amounts.Rd
index 41a5243..4886bed 100644
--- a/man/as_amounts.Rd
+++ b/man/as_amounts.Rd
@@ -36,7 +36,7 @@ totals(B)
 A2 <- as_amounts(B)
 
 ## Coerce to a data.frame
-X <- data.frame(B)
+X <- as.data.frame(B)
 head(X)
 }
 \seealso{
diff --git a/man/as_composition.Rd b/man/as_composition.Rd
index b08d315..870ff28 100644
--- a/man/as_composition.Rd
+++ b/man/as_composition.Rd
@@ -60,7 +60,7 @@ totals(B)
 A2 <- as_amounts(B)
 
 ## Coerce to a data.frame
-X <- data.frame(B)
+X <- as.data.frame(B)
 head(X)
 }
 \seealso{
diff --git a/man/mutators.Rd b/man/mutators.Rd
index 035a055..4ed4c82 100644
--- a/man/mutators.Rd
+++ b/man/mutators.Rd
@@ -32,6 +32,7 @@ Getters and setters to retrieve or set parts of an object.
 }
 \seealso{
 Other mutators: 
+\code{\link{as.data.frame}()},
 \code{\link{totals}()}
 }
 \author{
diff --git a/man/totals.Rd b/man/totals.Rd
index c3be161..f157860 100644
--- a/man/totals.Rd
+++ b/man/totals.Rd
@@ -49,11 +49,12 @@ totals(B)
 A2 <- as_amounts(B)
 
 ## Coerce to a data.frame
-X <- data.frame(B)
+X <- as.data.frame(B)
 head(X)
 }
 \seealso{
 Other mutators: 
+\code{\link{as.data.frame}()},
 \code{\link{mutators}}
 }
 \author{