To determine whether initial CD4 cell counts after human immunodeficiency virus (HIV) seroconversion have decreased over calendar time among participants in the Italian Seroconversion Study, HIV seroconverters who between 1985 and 1992 had a documented negative serology followed by a positive serology within 12 months and a first CD4 cell measurement within 24 months of seroconversion (defined as midpoint of negative and positive HIV tests) were cross-tabulated by year of seroconversion. Linear regression methods were used to examine temporal trends in initial CD4 level after adjustment for age, lag time of seroconversion, lag time of CD4 cell measurement, risk group, and clinical center. Between 1985 and 1992, the overall median initial CD4 cell level after seroconversion was 660 microliters with a median lag time of 212 days and 137 days for seroconversion and first CD4 cell measurement, respectively. In univariate and multivariate models, the CD4 cell count increases of 4.3 and 4.2 cells microliters/year, respectively, were not statistically significant. These data do not identify a trend of lower CD4 counts following HIV seroconversion in Italy and suggest indirectly that HIV has probably not become more virulent between 1985 and 1992.