Objective: To test the effectiveness of an in-training program for practitioners in public child welfare organizations. Method: The sample consists of practitioners (N = 945) working in youth centers or in local community service centers. Data are collected through self-administered questionnaires prior to and after the program. Results: The data show that prior to the training program, there are few differences between workers according to their educational backgrounds. Following the training program, practitioners felt more competent, had acquired additional knowledge, and had changed some of their behaviors with families. If level of stress at work had slightly decreased, job satisfaction remained unchanged. Conclusion: Findings suggest that an in-service training program may contribute to increased knowledge and feeling of competence and to modified professional behaviors, but it is essential to develop more valid indicators of knowledge and skills necessary to perform child welfare practice. (Contains 1 figure and 7 tables.)