Geocoding is a method used to convert address information into geographical coordinates. It plays a vital role in displaying the relationship between geographic features and semantic information expressed in texts. The objective of this study is to reveal the quality of online geocoding from postal addresses in Turkey provided by Google Maps and Bing Maps services. The quality of geocoding services in urban areas is evaluated using two particular metrics; positional accuracy and address similarity. Positional accuracy measures the distances between point features obtained through the online geocoding and reference data. Address similarity indicates the relationship between two postal addresses based on a similarity index known as the Levenshtein distance. The same performance assessment was also made with the United States' address data to make comparisons and discussions. The results show that services have different geocoding capabilities in both countries because of the differences in the addressing formats.