AbstractSewage discharge to the marine environment constitutes an important problem faced by public health and environmental managers, and exerts great economic and social impact on shellfish‐producing areas. This study aims at characterizing the water quality and shellfish sanitary conditions of different growing areas on the northern coast of the São Paulo State. Seventy‐two samples of water and shellfish were enumerated for total and fecal coliforms, and were analyzed for the presence ofSalmonella. The most probable number ofVibrio parahaemolyticuswas also determined for shellfish samples. Shellfish contamination was directly related to the bacteriological pollution of the water, such that in growing areas not contaminated with sewage discharges, 100% of shellfish samples presented themselves as being safe to be consumed.Salmonellawas absent in all samples analyzed andV. parahaemolyticuswas present in lower densities in shellfish samples. The percentage of water samples that did not comply to the standard were much higher than those of shellfish samples, indicating the need to reevaluate the permitted values of the Brazilian legislation both for shellfish “in natura” and for growing waters. This study also establishes the need for a better management of shellfish‐producing areas, especially those more polluted, in parallel with the development of a Brazilian Shellfish Sanitation Program, in order to protect the quality of these organisms and consequently hu