This paper presents results from a study of mobile ticketing service acceptance in public transportation. The theoretical background of the study was drawn from technology acceptance and diffusion of innovation theories, which were augmented with issues related to mobile service features, as well as the mobile use situation. The resulting research model was tested with data gathered through a self-administered mail survey with 360 subjects. Our findings suggest that usefulness and benefits of the mobile ticketing service are perceived differently in different use situations and that use situation has a significant effect on use intention. The results indicate that traditional adoption models should be augmented with the use situation and mobility constructs to better understand and explain the specific factors, which determine the use of mobile services.