This study aims to describe the practicality and effectiveness of character education models integrated in the learning of Mathematics and Natural Sciences is based on broad-scale trials were conducted at Muhammadiyah Junior High School of Malang City. Type of research is class action research-based lesson study with full reference to the Susilo (2009). This study was conducted in two cycles, refers to the Spiral Model of Kemmis & Taggart (1988) and Lesson Study which refers to Lewis (2002). The results of an analysis of the feasibility study observation sheet and teacher responses indicate that the model developed is included in the category of practical on the cycle I and is very practical in the cycle II. This model is practical for several reasons, namely 1) the development of models adopt a pattern that has been set by the government, was developed based on the conditions and be flexible, 2) the model allows teachers to implement and adapt to the conditions of the school or class being taught, 3) model has been developed passed the stage of planning, implementation, and evaluation involving teachers through the process of discussion and trial and supported by the feel of lesson study. The effectiveness of the model is included in the category of less or low in Cycle I and quite good in Cycle II. The values of the characters are already being integrated in the learning of Mathematics and Natural Sciences. Although the values of the characters that appear only include medium category, but gently push the teacher models for students’ attention to aspects of the character
Keywords: Character, Learning, Mathematics, Muhammadiyah, Natural Sciences