--- a/calendar/base/backend/icaljs/calICSService.js
+++ b/calendar/base/backend/icaljs/calICSService.js
@@ -47,16 +47,26 @@ calIcalProperty.prototype = {
     if (this.innerObject.type == "text") {
       this.innerObject.setValue(val);
       return;
     }
     this.valueAsIcalString = val;
   },
 
   get valueAsIcalString() {
+    let propertyStr = this.innerObject.toICALString();
+    if (propertyStr.match(/:/g).length == 1) {
+      // For property containing only one colon, e.g. `GEO:latitude;longitude`,
+      // the left hand side must be the property name, the right hand side must
+      // be property value.
+      return propertyStr.slice(propertyStr.indexOf(":") + 1);
+    }
+    // For property containing many or no colons, retrieve the property value
+    // according to its type. An example is
+    // `ATTENDEE;MEMBER="mailto:foo@example.com": mailto:bar@example.com`
     let type = this.innerObject.type;
     return this.innerObject
       .getValues()
       .map(val => {
         if (type == "text") {
           return ICAL.stringify.value(val, type, ICAL.design.icalendar);
         } else if (typeof val == "number" || typeof val == "string") {
           return val;

--- a/calendar/test/unit/test_ics_service.js
+++ b/calendar/test/unit/test_ics_service.js
@@ -177,16 +177,21 @@ function test_icalproperty() {
   equal(prop.valueAsIcalString, "A\\nB");
   equal(prop.valueAsDatetime, null);
 
   prop = svc.createIcalProperty("DESCRIPTION");
   prop.value = "A\\nB";
   equal(prop.value, "A\\nB");
   equal(prop.valueAsIcalString, "A\\\\nB");
   equal(prop.valueAsDatetime, null);
+
+  prop = svc.createIcalProperty("GEO");
+  prop.value = "43.4913662534171;12.085559129715";
+  equal(prop.value, "43.4913662534171;12.085559129715");
+  equal(prop.valueAsIcalString, "43.4913662534171;12.085559129715");
 }
 
 function test_icalcomponent() {
   let svc = cal.getIcsService();
   let event = svc.createIcalComponent("VEVENT");
   let alarm = svc.createIcalComponent("VALARM");
   event.addSubcomponent(alarm);