We investigated the evolution of the panmictic experimental populations of Drosophila melanogaster under the influence of artificial selection for reduced fitness. Slowly developing flies were selected among offspring from parents with low sexual activity and low fecundity. As result of this selection carried out for 16 generations, there was a strong decline in the various components of fitness. Our results confirm the results of the experiments by Kaidanov and his staff. The more rapid decrease in fitness observed by us seems to be due to the use of panmictic populations instead of inbred lines. Thus, the resulting fly selection observed in our studies likely reflects a preexisting genetic variation, rather than new mutations.