diff --git a/session.go b/session.go
index edd43f717..61a9cb22d 100644
--- a/session.go
+++ b/session.go
@@ -342,6 +342,7 @@ func ParseURL(url string) (*DialInfo, error) {
 	var readPreferenceTagSets []bson.D
 	minPoolSize := 0
 	maxIdleTimeMS := 0
+	safe := Safe{}
 	for _, opt := range uinfo.options {
 		switch opt.key {
 		case "authSource":
@@ -352,6 +353,23 @@ func ParseURL(url string) (*DialInfo, error) {
 			service = opt.value
 		case "replicaSet":
 			setName = opt.value
+		case "w":
+			safe.WMode = opt.value
+		case "j":
+			journal, err := strconv.ParseBool(opt.value)
+			if err != nil {
+				return nil, errors.New("bad value for j: " + opt.value)
+			}
+			safe.J = journal
+		case "wtimeoutMS":
+			timeout, err := strconv.Atoi(opt.value)
+			if err != nil {
+				return nil, errors.New("bad value for wtimeoutMS: " + opt.value)
+			}
+			if timeout < 0 {
+				return nil, errors.New("bad value (negative) for wtimeoutMS: " + opt.value)
+			}
+			safe.WTimeout = timeout
 		case "maxPoolSize":
 			poolLimit, err = strconv.Atoi(opt.value)
 			if err != nil {
@@ -394,7 +412,7 @@ func ParseURL(url string) (*DialInfo, error) {
 				return nil, errors.New("bad value for minPoolSize: " + opt.value)
 			}
 			if minPoolSize < 0 {
-				return nil, errors.New("bad value (negtive) for minPoolSize: " + opt.value)
+				return nil, errors.New("bad value (negative) for minPoolSize: " + opt.value)
 			}
 		case "maxIdleTimeMS":
 			maxIdleTimeMS, err = strconv.Atoi(opt.value)
@@ -402,7 +420,7 @@ func ParseURL(url string) (*DialInfo, error) {
 				return nil, errors.New("bad value for maxIdleTimeMS: " + opt.value)
 			}
 			if maxIdleTimeMS < 0 {
-				return nil, errors.New("bad value (negtive) for maxIdleTimeMS: " + opt.value)
+				return nil, errors.New("bad value (negative) for maxIdleTimeMS: " + opt.value)
 			}
 		case "connect":
 			if opt.value == "direct" {
@@ -437,6 +455,7 @@ func ParseURL(url string) (*DialInfo, error) {
 			Mode:    readPreferenceMode,
 			TagSets: readPreferenceTagSets,
 		},
+		Safe:           safe,
 		ReplicaSetName: setName,
 		MinPoolSize:    minPoolSize,
 		MaxIdleTimeMS:  maxIdleTimeMS,
@@ -529,6 +548,9 @@ type DialInfo struct {
 	// Session.SetMode and Session.SelectServers.
 	ReadPreference *ReadPreference
 
+	// Safe mostly defines write options, though there is RMode. See Session.SetSafe
+	Safe Safe
+
 	// FailFast will cause connection and query attempts to fail faster when
 	// the server is unavailable, instead of retrying until the configured
 	// timeout period. Note that an unavailable server may silently drop
@@ -715,6 +737,8 @@ func DialWithInfo(dialInfo *DialInfo) (*Session, error) {
 		return nil, err
 	}
 
+	session.SetSafe(&info.Safe)
+
 	if info.ReadPreference != nil {
 		session.SelectServers(info.ReadPreference.TagSets...)
 		session.SetMode(info.ReadPreference.Mode, true)
diff --git a/session_test.go b/session_test.go
index 14cb9b1a6..23396434d 100644
--- a/session_test.go
+++ b/session_test.go
@@ -168,6 +168,43 @@ func (s *S) TestURLInvalidReadPreference(c *C) {
 	}
 }
 
+func (s *S) TestURLSafe(c *C) {
+	type test struct {
+		url  string
+		safe mgo.Safe
+	}
+
+	tests := []test{
+		{"localhost:40001?w=majority", mgo.Safe{WMode: "majority"}},
+		{"localhost:40001?j=true", mgo.Safe{J: true}},
+		{"localhost:40001?j=false", mgo.Safe{J: false}},
+		{"localhost:40001?wtimeoutMS=1", mgo.Safe{WTimeout: 1}},
+		{"localhost:40001?wtimeoutMS=1000", mgo.Safe{WTimeout: 1000}},
+		{"localhost:40001?w=1&j=true&wtimeoutMS=1000", mgo.Safe{WMode: "1", J: true, WTimeout: 1000}},
+	}
+
+	for _, test := range tests {
+		info, err := mgo.ParseURL(test.url)
+		c.Assert(err, IsNil)
+		c.Assert(info.Safe, NotNil)
+		c.Assert(info.Safe, Equals, test.safe)
+	}
+}
+
+func (s *S) TestURLInvalidSafe(c *C) {
+	urls := []string{
+		"localhost:40001?wtimeoutMS=abc",
+		"localhost:40001?wtimeoutMS=",
+		"localhost:40001?wtimeoutMS=-1",
+		"localhost:40001?j=12",
+		"localhost:40001?j=foo",
+	}
+	for _, url := range urls {
+		_, err := mgo.ParseURL(url)
+		c.Assert(err, NotNil)
+	}
+}
+
 func (s *S) TestMinPoolSize(c *C) {
 	tests := []struct {
 		url  string