Comparing　two　proportions　through　the　difference　is　a　basic　problem　in　statistics　and　has　applications　in　many　fields.　More　than　twenty　confidence　intervals　(Newcombe,　1998a,b)　have　been　proposed.　Most　of　them　are　approximate　intervals　with　an　asymptotic　infimum　coverage　probability　much　less　than　the　nominal　level.　In　addition,　large　sample　may　be　costly　in　practice.　So　exact　optimal　confidence　intervals　become　critical　for　drawing　valid　statistical　inference　with　accuracy　and　precision.　Recently,　Wang　(2010,　2012)　derived　the　exact　smallest　(optimal)　one-sided　1　-　alpha　confidence　intervals　for　the　difference　of　two　paired　or　independent　proportions.　His　intervals,　however,　are　computer-intensive　by　nature.　In　this　article,　we　provide　an　R　package　ExactCIdiff　to　implement　the　intervals　when　the　sample　size　is　not　large.　This　would　be　the　first　available　package　in　R　to　calculate　the　exact　confidence　intervals　for　the　difference　of　proportions.　Exact　two-sided　1　-　alpha　interval　can　be　easily　obtained　by　taking　the　intersection　of　the　lower　and　upper　one-sided　1　-　alpha/2　intervals.　Readers　may　jump　to　Examples　1　and　2　to　obtain　these　intervals.