This research aims to study the demand for managerial accounting information of SMEs business entrepreneurs on Mueang Nonthaburi district at Nonthaburi Province and the relationships and effects of the demand for managerial accounting information on the operational success, by using a questionnaire as an instrument for collecting data from 81 SMEs business entrepreneurs on Mueang Nonthaburi district at Nonthaburi Province, of which 67 responses were returned. The findings revealed that the SMEs business entrepreneurs on Mueang Nonthaburi district at Nonthaburi Province agreed with having the demand for managerial accounting information as a whole and in each of all the aspects at a high level : planning, directing, controlling, and decision making. They also agreed with having operational success as a whole at a medium level : financial perspectives, customer perspectives, internal process and growth perspectives. According to analyses of the data in terms of relationships and effects, the followings were found the demand for managerial accounting information of SMEs business entrepreneurs on Mueang Nonthaburi district at Nonthaburi Province in the aspect of planning and controlling had positive relationships with and effects on the operational success significantly at 0.05.