Composition and seasonal distribution of limnetic rotifers in Douglas Lake, Michigan were investigated during the period January through December 1974 and compared with a historical 1938-1939 rotifer data base. Egg ratio data for the most abundant species was also accrued to evaluate the significance of the seasonal peaks of abundance observed for particular species. The high correlation between egg ratios and standing crops suggested that at least the major peaks were real and not the result of horizontal patchiness. No significant differences in the rotifer community or in the seasonal distribution could be detected between the two collections. Apparent differences in the species composition could be attributed to more recent changes in rotifer systematics and to the more thorough sampling routine of the recent study. However, the 1974 data set showed a significant increase in the spring maximum standing crop of rotifers. This increase suggests a change in trophic condition which may have resulted from lakeshore development during the past three decades.