Objective To investigate the degree and characteristics of Blattella germanica infestation in the restaurants of Tianjin, China and the influential factors, and to provide a scientific basis for the development of cockroach control measures. Methods The infestation rate, population density, and density index of B. germanica were monitored using sticky traps in 540 restaurants in 18 counties or districts of Tianjin. Results The mean infestation rate of B. germanica in the restaurants of Tianjin was 43.9%, and the mean population density and density index were 3.7 individuals/trap and 20.6 individuals/room, respectively. The population density of B. germanica was relatively high in the operating room, cold meat room, pastry room, and food warehouse, where the refrigerator radiator, dressing storage cabinet, and repository of pastry materials and sweets were the main places infested. The infestation rates of B. germanica in urban areas and villages/towns were 43.0% and 44.8%, respectively, without significant difference between them (P>0.05). The infestation rates of B. germanica in small and medium-sized restaurants and large restaurants were 43.4% and 45.1%, respectively, without significant difference between them (P>0.05). The infestation rates of B. germanica in restaurants with an operating period less than 5 years, restaurants with an operating period of 5-10 years, and restaurants with an operating period greater than 10 years were 33.9%, 57.6%, and 56.9%, respectively, with significant differences between them (P<0.01). The univariate logistic regression analysis showed that the operating period was an influential factor for the infestation rate of B. germanica in restaurants (OR=1.833, P<0.05). Conclusion The restaurants in Tianjin are heavily infested with B. germanica, so surveillance and early control should be enhanced, particularly at the refrigerator radiator, dressing storage cabinet, and repository of pastry materials and sweets in operating room, cold meat room, pastry room, and food warehouse.