Abstract: In Singapore the solving of mathematical word problems is a major component both within the instructional programme as well as during formal assessments. Research has indicated that both language and semantic structures play a part in determining pupils’ performance in the solving of mathematical word problems. This study aimed to determine if Primary 5 pupils' language proficiency and the rewording of mathematical word problems according to some semantic structures could affect the pupils’ problem solving process. The findings of this study revealed that the pupils’ English proficiency did not affect performance in solving the word problems. However certain rewording constructs like “chronological order of events” and “repositioning of givens” positively affected the low- and average-ability pupils.