The seminal volumes of 4223 men with known periods of abstinence of ejaculation, complete collections and with no dysfunction known to affect production of accessory gland secretions have been examined to define a minimum value for hyperspermia. The 95th percentile of the skewed data distribution was 6.3 ml and of the 229 men with values equal to or greater than this, 113 (49.3%) had sperm concentrations below the World Health Organization accepted minimum 'normal' value of 20 x 10(6)/ml. Basic seminal parameters should not be forgotten when assessing infertile men.