diff --git a/src/Network/Minio/PutObject.hs b/src/Network/Minio/PutObject.hs
index d3601b7..7c9ab2a 100644
--- a/src/Network/Minio/PutObject.hs
+++ b/src/Network/Minio/PutObject.hs
@@ -22,11 +22,12 @@ module Network.Minio.PutObject
   ) where
 
 
-import qualified Data.Conduit as C
-import qualified Data.Conduit.Binary as CB
+import qualified Data.ByteString.Lazy     as LBS
+import qualified Data.Conduit             as C
+import qualified Data.Conduit.Binary      as CB
 import qualified Data.Conduit.Combinators as CC
-import qualified Data.Conduit.List as CL
-import qualified Data.List as List
+import qualified Data.Conduit.List        as CL
+import qualified Data.List                as List
 
 import           Lib.Prelude
 
@@ -59,7 +60,19 @@ data ObjectData m
 -- objects of all sizes, and even if the object size is unknown.
 putObjectInternal :: Bucket -> Object -> PutObjectOptions
                   -> ObjectData Minio -> Minio ETag
-putObjectInternal b o opts (ODStream src sizeMay) = sequentialMultipartUpload b o opts sizeMay src
+putObjectInternal b o opts (ODStream src sizeMay) = do
+  case sizeMay of
+    -- unable to get size, so assume non-seekable file and max-object size
+    Nothing -> sequentialMultipartUpload b o opts (Just maxObjectSize) src
+
+    -- got file size, so check for single/multipart upload
+    Just size ->
+      if | size <= 64 * oneMiB -> do
+             bs <- C.runConduit $ src C..| CB.sinkLbs
+             putObjectSingle' b o (pooToHeaders opts) $ LBS.toStrict bs
+         | size > maxObjectSize -> throwM $ MErrVPutSizeExceeded size
+         | otherwise -> sequentialMultipartUpload b o opts (Just size) src
+
 putObjectInternal b o opts (ODFile fp sizeMay) = do
   hResE <- withNewHandle fp $ \h ->
     liftM2 (,) (isHandleSeekable h) (getFileSize h)
diff --git a/src/Network/Minio/S3API.hs b/src/Network/Minio/S3API.hs
index 363c244..9065ce3 100644
--- a/src/Network/Minio/S3API.hs
+++ b/src/Network/Minio/S3API.hs
@@ -42,6 +42,7 @@ module Network.Minio.S3API
   ---------------------------------
   , putBucket
   , ETag
+  , putObjectSingle'
   , putObjectSingle
   , copyObjectSingle
 
@@ -90,6 +91,7 @@ module Network.Minio.S3API
   ) where
 
 import           Control.Monad.Catch               (Handler (..), catches)
+import qualified Data.ByteString                   as BS
 import qualified Data.Conduit                      as C
 import           Data.Default                      (def)
 import qualified Data.Text                         as T
@@ -143,6 +145,28 @@ putBucket bucket location = void $
 maxSinglePutObjectSizeBytes :: Int64
 maxSinglePutObjectSizeBytes = 5 * 1024 * 1024 * 1024
 
+putObjectSingle' :: Bucket -> Object -> [HT.Header] -> ByteString -> Minio ETag
+putObjectSingle' bucket object headers bs = do
+  let size = fromIntegral (BS.length bs)
+  -- check length is within single PUT object size.
+  when (size > maxSinglePutObjectSizeBytes) $
+    throwM $ MErrVSinglePUTSizeExceeded size
+
+  -- content-length header is automatically set by library.
+  resp <- executeRequest $
+          def { riMethod = HT.methodPut
+              , riBucket = Just bucket
+              , riObject = Just object
+              , riHeaders = headers
+              , riPayload = PayloadBS bs
+              }
+
+  let rheaders = NC.responseHeaders resp
+      etag = getETagHeader rheaders
+  maybe
+    (throwM MErrVETagHeaderNotFound)
+    return etag
+
 -- | PUT an object into the service. This function performs a single
 -- PUT object call, and so can only transfer objects upto 5GiB.
 putObjectSingle :: Bucket -> Object -> [HT.Header] -> Handle -> Int64
diff --git a/test/LiveServer.hs b/test/LiveServer.hs
index 411d97f..59b6a58 100644
--- a/test/LiveServer.hs
+++ b/test/LiveServer.hs
@@ -124,6 +124,29 @@ lowLevelMultipartTest = funTestWithBucket "Low-level Multipart Test" $
       step  "Cleanup actions"
       removeObject bucket object
 
+putObjectSizeTest :: TestTree
+putObjectSizeTest = funTestWithBucket "PutObject of conduit source with size" $
+  \step bucket -> do
+      -- putObject test (conduit source, size specified)
+      let obj = "msingle"
+          mb1 = 1 * 1024 * 1024
+
+      step "Prepare for putObject with from source with size."
+      rFile <- mkRandFile mb1
+
+      step "Upload single file."
+      putObject bucket obj (CB.sourceFile rFile) (Just mb1) def
+
+      step "Retrieve and verify file size"
+      destFile <- mkRandFile 0
+      fGetObject bucket obj destFile def
+      gotSize <- withNewHandle destFile getFileSize
+      liftIO $ gotSize == Right (Just mb1) @?
+        "Wrong file size of put file after getting"
+
+      step "Cleanup actions"
+      deleteObject bucket obj
+
 putObjectNoSizeTest :: TestTree
 putObjectNoSizeTest = funTestWithBucket "PutObject of conduit source with no size" $
   \step bucket -> do
@@ -280,6 +303,7 @@ liveServerUnitTests = testGroup "Unit tests against a live server"
   , listingTest
   , highLevelListingTest
   , lowLevelMultipartTest
+  , putObjectSizeTest
   , putObjectNoSizeTest
   , funTestWithBucket "Multipart Tests" $
     \step bucket -> do