A simple apparatus to collect moving sperm by non-traumatic means which can be used for artificial insemination is described. The technique is based on enhancing the process of migration from the seminal fluid into a top-layered artificial medium in an ordinary test tube. This has been achieved by controlling 3 main variables: 1) The dilution of migrated sperm was minimize by using only 0.5 ml of the medium layered onto 1 ml semen; 2) increasing the surface area between these media by turning the test tube from a vertical to almost a horizontal position; 3) stimulating sperm activity by incubation at 37 degrees C under air: 5% CO2 for 30 min. When restored to a vertical position approximately 0.3 ml medium, sufficient for most AIH or IVF procedures, was gently aspirated. The effects of these variables on the rate of sperm migration was tested one at a time, and increments that ranged from 20% to as much as 10-fold were detected. When these 3 variables were optimized and 58 semen specimens analyzed, it was found that motility increased from 42 to 87%, velocity from 24.5 to 27.3 micron per sec, whilst abnormal forms dropped from 37 to 15%. The final concentration of motile sperm was 23 X 10(6)/ml compared to an original mean concentration of 34 X 10(6)/ml, indicating a relative recovery of 68%. Oligoasthenospermic specimens revealed similar changes in sperm motility, velocity, morphology and recovery. However, due to the low initial content of moving sperm (4.8 X 10(6)/ml), their final concentration was also low (2.7 X 10(6)/ml). Such specimens required additional preliminary preparation to increase the sperm concentration prior to the migratory procedure.