In response to Chinas rapidly developing economy, motorisation and increasing road traffic fatalities, the Chinese national road traffic safety law, requiring seatbelts to be worn where fitted, became effective May 2004. The research programme aimed to evaluate comparative changes in seatbelt wearing patterns in the contrasting Chinese cities of Nanjing, Jiangsu Province and Zhoushan, Zhejiang Province in 2005–2007. Following traffic familiarisation and piloting, roadside observations of urban seatbelt wearing were undertaken for 68 992 vehicles and 118 607 occupants. To interpret these results occupant interviews, focus groups and media reviews were conducted. Seatbelt wearing was significantly higher for drivers (49.9% Nanjing, 47.4% Zhoushan) than for front seat passengers (9.1% Nanjing, 1.0% Zhoushan) and virtually non-existent for rear passengers. Wearing generally declined significantly each year. An absence of child restraints and belt tampering, a practice of 12–15% of taxi drivers, was observed. Seatbelts were reported by interviewed drivers as fitted in almost all front and less than 50% of rear seats. Reasons for never wearing were most commonly feeling trapped and uncomfortable; for regular wearers feeling safer and not wanting to be fined. Focus group participants largely agreed on the need to wear seatbelts on highways in the front and not in the rear seat, agreement was lacking on wearing for slower city traffic. Media was not sustained. In conclusion there is need to promote awareness that injury can occur at relatively low speeds and to enforce correct wearing for taxi drivers. Wearing habits should be developed by consistent, visible and sustained enforcement.