This study examines the construct validity of the Mathematical Patterns Test using data from 848 Cypriot primary school students. Descriptive analyses across 5 age groups suggested a developmental structure of individual tasks and subdomains consistent with the design of the test. Acceptable fit was obtained using confirmatory factor analysis procedures for the theoretical 6-factor 1st-order structure. Results are discussed with reference to intended uses of the assessment and its score in the context of current reform in primary mathematics in Cyprus. (Contains 4 tables and 1 figure.)