diff --git a/.gitignore b/.gitignore
index c375723..eb5f126 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,5 @@
 *.o
 deps/usr
 deps/deps.jl
+*.wav
+*.flac
diff --git a/src/sndfile.jl b/src/sndfile.jl
index bf557be..9149c8b 100644
--- a/src/sndfile.jl
+++ b/src/sndfile.jl
@@ -5,6 +5,20 @@ const sndfile = "libsndfile"
 const SFM_READ = int32(0x10)
 const SFM_WRITE = int32(0x20)
 
+const SF_FORMAT_WAV =  0x010000
+const SF_FORMAT_FLAC = 0x170000
+const SF_FORMAT_OGG =  0x200060
+
+const SF_FORMAT_PCM_S8 = 0x0001 # Signed 8  bit data
+const SF_FORMAT_PCM_16 = 0x0002 # Signed 16 bit data
+const SF_FORMAT_PCM_24 = 0x0003 # Signed 24 bit data
+const SF_FORMAT_PCM_32 = 0x0004 # Signed 32 bit data
+
+const EXT_TO_FORMAT = [
+    ".wav" => SF_FORMAT_WAV,
+    ".flac" => SF_FORMAT_FLAC
+]
+
 type SF_INFO
     frames::Int64
     samplerate::Int32
@@ -25,12 +39,28 @@ type AudioFile
     sfinfo::SF_INFO
 end
 
-function af_open(path::String, mode::String="r")
-    # TODO: handle write/append modes
+function af_open(path::String, mode::String = "r",
+            sampleRate::Integer = 44100, channels::Integer = 1,
+            format::Integer = 0)
     sfinfo = SF_INFO(0, 0, 0, 0, 0, 0)
+    file_mode = SFM_READ
+
+    if mode == "w"
+        file_mode = SFM_WRITE
+        sfinfo.samplerate = sampleRate
+        sfinfo.channels = channels
+        if format == 0
+            _, ext = splitext(path)
+            sfinfo.format = EXT_TO_FORMAT[ext] | SF_FORMAT_PCM_16
+        else
+            sfinfo.format = format
+        end
+    end
+
     filePtr = ccall((:sf_open, sndfile), Ptr{Void},
                     (Ptr{Uint8}, Int32, Ptr{SF_INFO}),
-                    path, SFM_READ, &sfinfo)
+                    path, file_mode, &sfinfo)
+
     if filePtr == C_NULL
         errmsg = ccall((:sf_strerror, sndfile), Ptr{Uint8}, (Ptr{Void},), filePtr)
         error(bytestring(errmsg))
@@ -46,8 +76,8 @@ function Base.close(file::AudioFile)
     end
 end
 
-function af_open(f::Function, path::String)
-    file = af_open(path)
+function af_open(f::Function, args...)
+    file = af_open(args...)
     f(file)
     close(file)
 end
@@ -89,6 +119,28 @@ function Base.read(file::AudioFile, nframes::Integer = file.sfinfo.frames,
     return arr
 end
 
+function Base.write{T}(file::AudioFile, frames::Array{T})
+    nframes = int(length(frames) / file.sfinfo.channels)
+
+    if T == Int16
+        return ccall((:sf_writef_short, sndfile), Int64,
+                        (Ptr{Void}, Ptr{Int16}, Int64),
+                        file.filePtr, frames, nframes)
+    elseif T == Int32
+        return ccall((:sf_writef_int, sndfile), Int64,
+                        (Ptr{Void}, Ptr{Int32}, Int64),
+                        file.filePtr, frames, nframes)
+    elseif T == Float32
+        return ccall((:sf_writef_float, sndfile), Int64,
+                        (Ptr{Void}, Ptr{Float32}, Int64),
+                        file.filePtr, frames, nframes)
+    elseif T == Float64
+        return ccall((:sf_writef_double, sndfile), Int64,
+                        (Ptr{Void}, Ptr{Float64}, Int64),
+                        file.filePtr, frames, nframes)
+    end
+end
+
 type FilePlayer <: AudioNode
     active::Bool
     file::AudioFile
diff --git a/test/sinwave.flac b/test/sinwave.flac
deleted file mode 100644
index 739a247..0000000
Binary files a/test/sinwave.flac and /dev/null differ
diff --git a/test/test_AudioIO.jl b/test/test_AudioIO.jl
index 7d03f49..64de9d3 100644
--- a/test/test_AudioIO.jl
+++ b/test/test_AudioIO.jl
@@ -73,15 +73,25 @@ stop(node)
 process(test_stream)
 @test process(test_stream) == zeros(AudioIO.AudioSample, TEST_BUF_SIZE)
 
-info("Testing libsndfile read")
-samplerate = 44100
-freq = 440
-t = linspace(0, 2, 2 * samplerate)
-phase = 2 * pi * freq * t
-reference = int16((2 ^ 15 - 1) * sin(phase))
+for ext in ["wav", "flac"]
+    info("Testing $ext file write/read")
 
-f = af_open("test/sinwave.flac")
-@test f.sfinfo.channels == 1
-@test f.sfinfo.frames == 2 * samplerate
-actual = read(f, 2 * samplerate)
-@test_approx_eq(reference, actual)
+    fname = "test/sinwave.$ext"
+
+    samplerate = 44100
+    freq = 440
+    t = [0 : 2 * samplerate - 1] / samplerate
+    phase = 2 * pi * freq * t
+    reference = int16((2 ^ 15 - 1) * sin(phase))
+
+    af_open(fname, "w") do f
+        write(f, reference)
+    end
+
+    af_open(fname) do f
+        @test f.sfinfo.channels == 1
+        @test f.sfinfo.frames == 2 * samplerate
+        actual = read(f, 2 * samplerate)
+        @test_approx_eq(reference, actual)
+    end
+end