To assess the clinical utility of routine endocrine testing in women with adult-onset amenorrhea, charts were identified from 127 women diagnosed with adult-onset amenorrhea who had a thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH), and prolactin (PRL) level performed. Women who were pregnant or previously diagnosed with thyroid disease were subsequently excluded and 120 subjects remained. Of the 120 women screened, 12 (0.100) had abnormal FSH levels, 9 (0.075) had abnormal PRL levels, and 5 (0.042) had abnormal TSH levels. The incidence of an abnormal FSH level (95% CI 0.053, 0.168; p < 0.001) and PRL level (95% CI 0.035, 0.138; P = 0.007) was significantly elevated as compared to the reference laboratory normal values. However, the incidence of an abnormal TSH level in the study population was not statistically different from that of the reference laboratory normal values (95% CI 0.014, 0.095, p = 0.88). The evaluation of 120 women with adult-onset amenorrhea demonstrated abnormal concentrations of FSH, PRL and TSH in 10, 7.5 and 4.2% of patients, respectively. A rank ordering of these endocrine tests may be useful when evaluating women with adult-onset amenorrhea.