diff --git a/fco2/GenerateC.hs b/fco2/GenerateC.hs
index 13fb798..041a4db 100644
--- a/fco2/GenerateC.hs
+++ b/fco2/GenerateC.hs
@@ -1070,7 +1070,7 @@ genProcAlloc (A.ProcCall m n as)
     =  do tell ["ProcAlloc ("]
           genName n
           -- FIXME stack size fixed here
-          let stackSize = 4096
+          let stackSize = 65536
           tell [", ", show stackSize, ", ", show $ numCArgs as]
           genActuals as
           tell [")"]
diff --git a/fco2/kroc-wrapper-c.c b/fco2/kroc-wrapper-c.c
index fd275bc..a2e76f5 100644
--- a/fco2/kroc-wrapper-c.c
+++ b/fco2/kroc-wrapper-c.c
@@ -5,7 +5,7 @@
 extern void fco_main (Process *me, Channel *in, Channel *out, Channel *err);
 
 void _fco_main_init (int *ws) {
-	Process *p = ProcAlloc (fco_main, 4096, 3,
+	Process *p = ProcAlloc (fco_main, 65536, 3,
 	                        (Channel *) ws[1], (Channel *) ws[2], (Channel *) ws[3]);
 	*((int *) ws[0]) = (int) p;
 }