Description : Sinamaica Lagoon is a large extension of water located northwest of Zulia state, Venezuela. The Paraujano population or ethnic A?u that inhabit this area have been lived on the Lagoon, in stilted houses over the water ?palafitos?, since pre-colonial times. People living there, now estimated at 2800, use this body of water for fishing, transport, and other activities. According to available epidemiological data, enteritis is one of the principal causes of mortality in children from one to four in this zone. Water samples from ten different sites of the lagoon were taken monthly throughout a nine-month period. Microbiological parameters analyzed included: Most Probable Number (MPN) of total and faecal coliforms and faecal streptococci and enterococci (per 100 mL), Plate Forming Unit of coliphage (per 100 mL) and tests for the presence of Salmonella, Shigella and other Enterobacteriaceae. A wide range of distribution of the different faecal indicators was found: TC <3.0x100 - >2.4x103, FC 2.1x102 - 1.1x104, C 0 - 4.3x102 y FS y E <2.0x101 - 1.1x104. The Enterobacteriaceae most frequently isolated were Escherichia coli, Klebsiella and Enterobacter 30.53%, 19.08% and 15.26%, respectively. Shigella and Salmonella were present in 12.97% and 3.05% of total samples. Total and faecal coliform levels exceeded the Venezuelan guideline for recreational water, in more than 50% of the samples. We concluded that waters of Sinamaica Lagoon are microbiologically polluted and represent a health risk for its inhabitants.