Following a case history, the literature concerning hyponatremia associated with the use of selective serotonin reuptake inhibitors is reviewed. Discussed are presenting symptoms, pathofysiology, diagnosis and treatment. Although hyponatremia usually is considered to be a rare side effect of ssri's, higher percentages are reported in recent research reports. We offer the hypothesis that hyponatremia may not be a rare side effect, but a rarely diagnosed side effect of ssri's. In order to test this hypothesis, further research is needed.