Effective teaching of geographic information systems (gis) is hampered by limited spatial reasoning of students. The ability to reason about spatial relations, including the identification of spatial patterns and spatial associations, is important to geographic problem solving using a gis. In this paper, we report one aspect of a larger study that investigates how expertise in spatial thinking is related to strategies for solving geographic problems using a gis. To explore this relationship, research was conducted with 104 geography students in waterloo, ontario, canada. Students were drawn from four educational levels: grade 9 students, 13 to 14 years of age; 1st year undergraduate university students, 3rd and 4th year undergraduate geography majors; and geography students at the graduate level ranging from 22 to 32 years of age. Participants first responded to a 30-item scale differentiating spatial thinkers along a novice-expert continuum. Scores on the scale showed an increase in spatial reasoning with level of education, such that grade 9 students averaged 7.5 Out of 30 while the mean score of graduate students was 20.6. Students were then given a simple geographic problem to solve using a gis. Our analysis here examines the relationship between performance on the spatial reasoning scale and the observed problem solving strategies applied while using a gis. In general, students with lower scores were more apt to use basic visualization (zoom/measure tools) or buffer operations, while those with higher scores used a combination of buffers, intersection and spatial queries. There were, however, exceptions as some advanced students used strategies that overly complicated the problem while others used visualization tools alone. The findings show complexities in the relationship of spatial reasoning to geographic problem solving using a gis and suggest several practical implications for teaching with gis.