diff --git a/lib/pop3.h b/lib/pop3.h
index 20a226985..337421cac 100644
--- a/lib/pop3.h
+++ b/lib/pop3.h
@@ -43,8 +43,8 @@ typedef enum {
 struct pop3_conn {
   struct pingpong pp;
   char *mailbox;     /* what to RETR */
-  int eob;        /* number of bytes of the EOB (End Of Body) that has been
-                     received thus far */
+  size_t eob;        /* number of bytes of the EOB (End Of Body) that has been
+                        received thus far */
   pop3state state; /* always use pop3.c:state() to change state! */
 };
 
diff --git a/lib/smtp.c b/lib/smtp.c
index 2f7350b97..654f43505 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -1045,8 +1045,8 @@ CURLcode Curl_smtp_escape_eob(struct connectdata *conn, ssize_t nread)
    * the data and make sure it is sent as CRLF..CRLF instead, as
    * otherwise it will wrongly be detected as end of data by the server.
    */
-  int i;
-  int si;
+  ssize_t i;
+  ssize_t si;
   struct smtp_conn *smtpc = &conn->proto.smtpc;
   struct SessionHandle *data = conn->data;
 
@@ -1061,7 +1061,7 @@ CURLcode Curl_smtp_escape_eob(struct connectdata *conn, ssize_t nread)
   for(i = 0, si = 0; i < nread; i++, si++) {
     ssize_t left = nread - i;
 
-    if(left>= (SMTP_EOB_LEN-smtpc->eob)) {
+    if(left>= (ssize_t)(SMTP_EOB_LEN-smtpc->eob)) {
       if(!memcmp(SMTP_EOB+smtpc->eob, &data->req.upload_fromhere[i],
                  SMTP_EOB_LEN-smtpc->eob)) {
         /* It matched, copy the replacement data to the target buffer
diff --git a/lib/smtp.h b/lib/smtp.h
index fac43041a..4716338b5 100644
--- a/lib/smtp.h
+++ b/lib/smtp.h
@@ -47,8 +47,8 @@ typedef enum {
 struct smtp_conn {
   struct pingpong pp;
   char *domain;    /* what to send in the EHLO */
-  int eob;         /* number of bytes of the EOB (End Of Body) that has been
-                      received thus far */
+  size_t eob;         /* number of bytes of the EOB (End Of Body) that has been
+                         received thus far */
   smtpstate state; /* always use smtp.c:state() to change state! */
   struct curl_slist *rcpt;
 };