This research aims to understand the ability of deaf students to solve mathematical problem solving based on prior mathematical abilities. This research was conducted by using descriptive qualitative methods. Data collection techniques consists of tests, questionnaires, and interviews. The research subjects were deaf students in one of special schools in Bandung, Indonesia. The result of this study is problem solving abilities of 5 deaf students based on Prior Mathematics Ability. The result indicates one student has problem solving skills in a good category, three students are sufficient and the other one is in the low category. However, it does not mean that students who have Prior Mathematics Ability in a good category indicate that they also have good problem solving skills.