diff --git a/library/network/http_client/src/spec/libcurl/libcurl_http_client_request.e b/library/network/http_client/src/spec/libcurl/libcurl_http_client_request.e
index c3721a26..c46c8e9b 100644
--- a/library/network/http_client/src/spec/libcurl/libcurl_http_client_request.e
+++ b/library/network/http_client/src/spec/libcurl/libcurl_http_client_request.e
@@ -47,6 +47,7 @@ feature -- Execution
 			l_result: INTEGER
 			l_curl_string: detachable CURL_STRING
 			l_url: READABLE_STRING_8
+			l_use_curl_form: BOOLEAN
 			l_form: detachable CURL_FORM
 			l_last: CURL_FORM
 			l_upload_file: detachable RAW_FILE
@@ -166,19 +167,24 @@ feature -- Execution
 						if l_upload_data = Void and l_upload_filename = Void then
 							-- Send as form-urlencoded
 							if
-								l_headers.has_key ("Content-Type") and then
-								attached l_headers.found_item as l_ct
+								attached l_headers.item ("Content-Type") as l_ct
 							then
 								if l_ct.starts_with ("application/x-www-form-urlencoded") then
 									-- Content-Type is already application/x-www-form-urlencoded
 									l_upload_data := ctx.form_parameters_to_url_encoded_string
+								elseif l_ct.starts_with ("multipart/form-data") then
+									l_use_curl_form := True
 								else
-									-- Existing Content-Type and not application/x-www-form-urlencoded
+										-- Not supported, use libcurl form.
+									l_use_curl_form := True
 								end
 							else
 								l_upload_data := ctx.form_parameters_to_url_encoded_string
 							end
 						else
+							l_use_curl_form := True
+						end
+						if l_use_curl_form then
 							create l_form.make
 							create l_last.make
 							from
@@ -434,7 +440,7 @@ feature {NONE} -- Implementation
 		end
 
 note
-	copyright: "2011-2015, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
+	copyright: "2011-2017, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software
diff --git a/library/network/http_client/src/spec/net/net_http_client_request.e b/library/network/http_client/src/spec/net/net_http_client_request.e
index 5a3acfa5..8c9b1776 100644
--- a/library/network/http_client/src/spec/net/net_http_client_request.e
+++ b/library/network/http_client/src/spec/net/net_http_client_request.e
@@ -194,16 +194,36 @@ feature -- Access
 						if ctx.has_form_data then
 							l_form_data := ctx.form_parameters
 							if l_upload_data = Void and l_upload_filename = Void then
-									-- Send as form-urlencoded
-								headers.extend ("application/x-www-form-urlencoded", "Content-Type")
-								l_upload_data := ctx.form_parameters_to_url_encoded_string
-								headers.force (l_upload_data.count.out, "Content-Length")
+								if
+									attached headers.item ("Content-Type") as l_ct
+								then
+									if l_ct.starts_with ("application/x-www-form-urlencoded") then
+										l_upload_data := ctx.form_parameters_to_url_encoded_string
+									elseif l_ct.starts_with ("multipart/form-data") then
+											-- create form using multipart/form-data encoding
+										l_boundary := new_mime_boundary (l_form_data)
+										headers.extend ("multipart/form-data; boundary=" + l_boundary, "Content-Type")
+										l_upload_data := form_date_and_uploaded_files_to_mime_string (l_form_data, l_upload_filename, l_boundary)
+									else
+											-- not supported !
+											-- Send as form-urlencoded
+										headers.extend ("application/x-www-form-urlencoded", "Content-Type")
+										l_upload_data := ctx.form_parameters_to_url_encoded_string
+									end
+								else
+										-- Send as form-urlencoded
+									headers.extend ("application/x-www-form-urlencoded", "Content-Type")
+									l_upload_data := ctx.form_parameters_to_url_encoded_string
+								end
+								headers.extend (l_upload_data.count.out, "Content-Length")
 								if l_is_chunked_transfer_encoding then
 										-- Discard chunked transfer encoding
 									headers.remove ("Transfer-Encoding")
 									l_is_chunked_transfer_encoding := False
 								end
 							elseif l_form_data /= Void then
+								check l_upload_data = Void end
+
 									-- create form using multipart/form-data encoding
 								l_boundary := new_mime_boundary (l_form_data)
 								headers.extend ("multipart/form-data; boundary=" + l_boundary, "Content-Type")
@@ -400,9 +420,9 @@ feature -- Access
 								end
 
 									-- follow redirect
-								if 
+								if
 									is_redirection_http_status (Result.status) and
-									l_location /= Void 
+									l_location /= Void
 								then
 									if Result.redirections_count < max_redirects then
 										initialize (l_location, ctx)
@@ -906,7 +926,7 @@ feature {NONE} -- Helpers
 
 invariant
 note
-	copyright: "2011-2016, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
+	copyright: "2011-2017, Jocelyn Fiat, Javier Velilla, Eiffel Software and others"
 	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
 	source: "[
 			Eiffel Software