The distribution of suspended particles of different size is investigated using Landsat-TM in coastal waters near a sewage outfall, Sydney, Australia. Following a discussion of the relations between visible response and suspended particles a model is developed, via regression analysis, relating TM data and ocean sampled particle size data. This allowed the prediction of the number of particles in each of 36 classes of particle size. TM digital data was processed on the basis of the developed models to show the spatial distribution of both large and small particles. Large particles were found to be distributed near an ocean sewage outfall, while small particles were more widely distributed.