Using a gamma camera and specially developed micropinhole collimator, the dynamics of the lacrimal drainage apparatus in man were studied in vivo with a radioactive tracer for the first time. Because of the much lower dosage of radiation and the more physiologic nature of demonstrating the lacrimal apparatus, this technique is suggested as an adjunct or replacement for the radiopaque dye studies (dacryocystogram). This first reported use of microscintigraphy suggests applications in other medical disciplines.