The Carex crinita Lam. complex (Cryptocarpae) comprises eight validly described taxa occurring in eastern North America. Modern taxonomic treatments of the complex differ considerably recognizing from three to seven taxa of varying rank. For this study, 36 populations representing the range of morphological variation in the complex were examined utilizing starch gel electrophoresis and allozyme analysis. Data were collected for 18 putative genetic loci. Although 13 of these loci were variable across the species complex, only 15 populations were polymorphic at one or more loci. The number of alleles per locus averaged 1.06, whereas the average percentage of polymorphic loci was 5.26. The majority of genetic variation is distributed among taxa as evidenced by the values obtained for Nei's gene diversity statistic; a G_ST of 0.658 indicates that these populations are highly differentiated. Averaged by taxon, Nei's unbiased genetic identity ranged from 0.726 for pairwise comparisons of populations of C. gynandra and C. mitchelliana to 0.866 for C. gynandra and C. crinita var. brevicrinis. These data support the recognition of four taxa comprising this species complex. Additionally, statistically significant deviations from Hardy-Weinberg expected heterozygosity and high positive values for Wright's fixation index suggest high levels of inbreeding. These data contrast with morphological evidence suggesting outcrossing through wind dispersal of pollen.