The Virginia Community College System (VCCS) converted from a quarter to semester calendar at the beginning of the 1988-89 academic year. A study was conducted after the first year of the use of the new calendar to determine its effects on enrollment and student persistence. Full- and part-time enrollment data and student retention rates for 1988-89 were compared with data for previous years. Study findings included the following: (1) enrollment, as measured by annual full-time equivalent students (FTES), continued to increase at about the same rate as the previous two years; (2) though annual FTES for the system as a whole increased, fall term FTES decreased; (3) more full-time students, but fewer full-time degree students, were enrolled than in the previous fall quarter; (4) fewer part-time students were enrolled than in the previous fall quarter; (5) the enrollment of 18 to 21 year-old full-time students continued to increase at approximately the same rate as the previous two years; (6) the number of full-time occupational degree students decreased at 15 of the 23 colleges in the VCCS, while the number of full-time university parallel students increased at 18 of the colleges; (7) all but one of the colleges experienced an increase in the retention of full-time degree students from the fall to the spring terms; (8) the retention rate for the system as a whole increased from 76.5% to 83.0%; and (9) productive grades were highly correlated with student retention, particularly for full-time university parallel degree students. (JMC)