This study describes the problem solving behaviour of bilingual (German - Turkish) primary school students, their approaches and preferences while solving the word problems. Four different types of mathematical word problems (combinations, movement, subtraction and addiction) were given successively to four pupils (one girl and three boys) and their individual strategies during solution process were explored. After examining the students' answers, four theme, namely language, effect of daily experience, recontextualizing the problem and the mathematical answer were listed. Generally, the students struggle to use the representations effectively with their problem solving strategies. This study would be valuable with giving detailed information about bilingual students problems solving strategies under free language environment and results would be helpful to researchers to conduct an intervention study that specially targeting to improve the problems solving strategies of bilingual children with an emphasize to rehearsal their reading skills and representation repertoire.