Over the years, the role and extent of the basic sciences in medical curricula have been challenged by research on clinical expertise, clinical teachers, and medical students, as well as by the development and diversification of the medical curricula themselves. The aim of this study was to examine how prior knowledge of basic histology and histopathology among students predicts early learning of diagnostic pathology. Participants ("N" = 118, representing 91% of the full student cohort) were medical students at the University of Turku, Finland. Data were collected during two preclinical courses that students attended in their first and second years of medical school. The measurements included tests on biomedical and clinical knowledge and a performance test in diagnostic pathology. Second-year performance on the diagnostic pathology examinations was predicted by the students' prior knowledge of histology, but not by the students' prior knowledge of histopathology. Although earlier research has demonstrated similar results in studies with shorter longitudinal designs, the present study demonstrates that the effect remains even if there is a considerably long time delay (a year) between the measurements, thus confirming the long-term value of basic science studies in the preclinical phase.