Katie Zhan is one of Carl Johnson's optional girlfriends. She is a nurse who also spends her spare time at the karate dojo in San Fierro, San Andreas. Due to her health-concious image, she eats at diners but avoids fast food restaurants. Katie also likes the shoreline and her mood improves when the player drives by the area, especially by the Gant Bridge. She doesn't like the Queens neighborhood. She is also fascinated by automobile accidents and is easily aroused by reckless driving.
She can initially be found at the northeast corner of Avispa Country Club at the south end of the city, practicing martial arts behind some bushes. She can be seen easily from the road. Katie likes men with sex appeal and muscle, so bulk up before asking her out.
Katie lives in the Juniper Hollow district of San Fierro, at the northwest corner of the city, just southeast of the Gant Bridge and the nearest home to it. She is usually at home between 12:00 and 00:00.
There is a glitch which commonly occurs in the gameplay. If a player dates Katie in one game and starts a new game and does not date her, they can usually find after being wasted that their weapons are still with them.
Katie prefers diners. The nearest is right down the hill from her place, in a roadside diner next to the Gant Bridge information centre.
Despite her dislike of the area, the Gaydar Station club is the closest dance club to take Katie to.
Katie seems to prefer areas close to the shoreline, so options include driving around the area below the Gant Bridge and Jizzy's Pleasure Domes (including the latter's parking lot), or the Bayside area across the bridge. She also loves being driven around in Chinatown. She seems to prefer a moderate driving speed; although she will at times encourage Carl to drive faster, in fact doing so makes her Fun meter drop. She also appears to be aroused when Carl collides with anything, although this doesn't appear to affect either the Fun meter or Progress statistic. Steer clear of the Queens area during this date as she dislikes it. An alternative less time consuming way of passing this date is to simply drive around Katies housing block at a moderate speed and you will be sure to pass the date.
- Dating Katie will allow the player to get out of the hospital for free, and they will also get to keep all of their weapons after dying, a form of universal healthcare not found in other Grand Theft Auto games (except GTA IV where you keep your weapons but still need to pay). If Carl is wasted in San Fierro he will hereafter spawn outside Katie's house rather than the hospital.
- At 50%: Katie will give the player the keys to her white Romero.
- At 100%: Katie will give the player the medic uniform, which consists of a white shirt emblazoned with the standard medical Star of Life and dark blue pants.
- Katie's car has the license plate reading "TRAUMA" suggesting she works with trauma victims in the hospital.
- If the player takes her on a driving date, she will encourage Carl to drive faster, but if the player does so, the "fun" meter will go down, and text will inform the player that they are driving too fast. It's possible that she is being sarcastic.
- In some safehouses and houses in the Burglary side mission a photo of Katie with another unnamed person can be seen. The same photo can also be seen in Maria Latore's apartment in Grand Theft Auto: Liberty City Stories.
- During random conversations while on a date, she mentions that she's a fan of Madd Dogg, dislikes OG Loc ("OG Joke is more like it") and is disturbed by the Epsilon Program.
- During some food dates, Katie has her eyes closed in the cutscenes.