Gonadotrophin-induced ovulation (GnOI) is generally an effective treatment when anti-estrogen therapy is unsuccessful. It remains uncertain how appropriate it is in older and obese women. We carried out an analysis of a GnOI programme between 2000 and 2008, including 514 treatment cycles in 140 women with World Health Organisation Group II anovulation. A low-dose step-up stimulation protocol using recombinant follicle stimulating hormone (FSH) (with natural intercourse) was used throughout in the treatment of women aged up to 40 years and with body mass index (BMI) up to 34 kg/m(2), with a rigorously-applied cancellation criterion. The livebirth rates in first stimulated cycle and cumulatively over six cycles (or until pregnancy) were 19.2% and 74.2%, respectively and the multiple livebirth rate was 2.5%. There was no significant relationship between age and BMI with pregnancy rates, although higher BMI was associated with higher threshold dose and longer duration of stimulation. Anti-estrogen resistant patients attained significantly higher cumulative ongoing pregnancy rates than those who were anti-estrogen responsive. These data demonstrate that judicious administration of gonadotrophins to women with WHO Group II anovulatory subfertility can result in a good pregnancy rate with low risk of multiple pregnancy in women aged up to 40 years and with BMI of up to 34 kg/m(2).