To increase the sample-handling capacity for an induction of ovulation programme, direct urinary radioimmunoassays (RIA) for three steroid glucuronides, pregnanediol-3-glucuronide (Pd-3-G), oestrone-3-glucuronide (E1-3-G), and oestriol-16 alpha-glucuronide (E3-16-G), were established. Results obtained for urinary Pd-3-G measured by direct RIA show an excellent correlation (r = 0.98, N = 46) with those for urinary pregnanediol measured by gas-liquid chromatography. Estrone-3-glucuronide (E1-3-G) and estriol-16 alpha-glucuronide (E3-16-G) values, measured by direct RIA, closely paralleled the total urinary oestrogen measured fluorimetrically. Ovarian response to ovulation induction therapy can be monitored by observing the changes in the levels of E1-3-G in urine. Pre-ovulatory levels of urinary E3-16-G were found to be too low for use in this regard. Direct RIA for E1-3-G and Pd-3-G are recommended as reliable indices of ovarian function in the monitoring of patients receiving treatment for the induction of ovulation.