DENG and LYNCHre cently proposeda method for estimating deleterious genomic mutation parameters from changes in the mean and genetic variancoef fitness traits upon inbreeding in outcrossing populations. Such observations are readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. We observed a significant inbreeding depression and an increase of genetic variance for all traits analyzed. DENC and LYNCH's original proceduresw ere extended to estimate genomic mutation rate (U), mean dominance coefficient (A), mean selection coefficient (3), and scaled genomic mutational variance (Vm/Ve). On average, Û, h/ˆ, s/ˆand Vm/V (A indicates an estimate) are 0.74, 0.30, 0.14 and 4.6E-4, respectjvely. For the true values, the Û and h/∮are lower bounds, and s/ˆ and Vˆm/Ve upper bounds. The presenat Û, h/ˆ and Vˆm/Ve are in general concordance with earlier results. The discrepancy between the present Sand thfraot m mutation-accumulation experiments in Drosophila (～0.04) is discussed. It is shown that different reproductive modes do not affect gene frequency at mutationselection equilibrium if mutational effects on fitness are multiplicative and not completely recessive.