Pseudomonas sp. is a hydrocarbonoclastic bacteria that is capable of degrading various types of hydrocarbons. Pseudomonas sp. including bacteria that have the potential to become pathogens. This research was conducted in April to May 2018. This study aims to calculate the density of Pseudomonas sp. Bacteria and heterotrophic bacteria in Dumai sea waters, comparison of the desity of Pseudomonas …