diff --git a/src/fits.jl b/src/fits.jl
index cdcd14b..6a18350 100644
--- a/src/fits.jl
+++ b/src/fits.jl
@@ -125,6 +125,13 @@ function getindex(f::FITS, name::AbstractString, ver::Int=0)
     return f.hdus[i]
 end
 
+Base.haskey(f::FITS, i::Integer) = i ∈ 1:length(f)
+
+Base.haskey(f::FITS, name::AbstractString) = any(1:length(f)) do i
+    fits_movabs_hdu(f.fitsfile, i)
+    fits_try_read_extname(f.fitsfile) == name
+end
+
 """
     deleteat!(f::FITS, i::Integer)
 
diff --git a/test/runtests.jl b/test/runtests.jl
index aab8084..aba9011 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -403,6 +403,10 @@ end
                 write(f, a, name="a")
                 @test read(f["a"]) == a
                 @test read(f[1])   == a
+                @test haskey(f, "a")
+                @test !haskey(f, "b")
+                @test haskey(f, 1)
+                @test !haskey(f, 2)
             end
         end
     end