PointSource Technologies is developing a new flow-through detection and enumerationmethod that shows strong potential for use as an on-line, continuous, and real-time system for Cryptosporidium and Giardia. PointSource has adapted a technique called multi-angle light scattering (MALS) to the problem of drinking water qualitymonitoring. In initial laboratory tests performed with low turbidity water, it was found that the light scattering patterns of Cryptosporidium, Giardia, and a background of seven different types of algae were sufficiently unique to discriminate between the pathogens and the background. The identification rates were approximately 60% for Cryptosporidium and 75% for Giardia, with confidence levels exceeding 90%. False positive rates were low, around 1% and 3.5%, respectively. Includes 12 references, tables, figures.