The German cockroaches are pest insects in the housing areas and other places such as in the cars, ships and public transportations that are not well sanitized.  One of the safest way to control these pest insects in these sensitive areas is using baits.  However, the effectiveness of a bait formulation is dependent on the self-selection behaviour of the cockroaches againsts bait components.  The purpose of this research is to assess the self-selection behaviour of the German cockroaches on diets with different nutritional compositions.  The treatments consisted of a diet with the ratio of casein:sucrose 100:0, 80:20, 50:50, 20:80, and 0:100. The cockroaches used were males. The observed behavioral parameters included latency, frequency, and duration of visits to the diet. Behavioral observations were conducted for 24 hours (6:00 pm – 6:00 am) using the recording and continous sampling method. The Data obtained were analyzed by using one way anova. The results showed that the nutritional composition of the diet did not affect latency, but it affected the frequency of visits to the diet and the duration of the cockroach on a diet (p < 0.05). The highest visit frequency (15.67 times) and the longest duration (2,066,667 seconds) were on the diet with the composition of casein:sucrose 20:80.  The German cockroaches orientated randomly at the beginning of choosing a diet and seemed that the diet with the composition of casein:sucrose 20:80 was most preferred than any other diet compositions.