Running is associated with an increase in plasma concentrations of certain anterior pituitary hormones and adrenal steroids. This study reports such increases after a marathon race. Six trained female runners, 26 to 42 years old, participated in a marathon race. Fasting (resting) blood samples were collected a few weeks before the race (baseline) and immediately (0 hour), 1 hour, and 4 hours after the run. The data were analyzed with the use of two-way analyses of variance (F-test), paired t-test, and Page's test. At 0 hour, compared with baseline, significant increases were observed in the plasma concentrations of testosterone (T), dehydroepiandrosterone sulfate (DHEA-S), cortisol (F), free T index (T/SHBG), and prolactin (PRL). At 1 hour, levels of these steroid hormones and PRL declined, some significantly. At 4 hours, levels of all hormones except DHEA-S returned to baseline. No significant changes were observed in concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and sex hormone-binding globulin (SHBG), as evaluated by F-test. Running-associated changes in plasma hormonal concentrations revert to baseline in four hours, although DHEA-S may take a little longer.