Mahyaveh is an Iranian fermented fish sauce produced from fish, salt, spices and water during fermentation period. The main problem related to this product is very high histamine content of it. Effects of starter cultures (Lactobacillus plantarum and Paenibacillus polymyxa) on reduction of histamine in mahyaveh, as “Southern Iran Fermented Fish Sauce” were investigated. This study was performed in 4 experimental groups, including control and treatments on 30th and 45th days of the product. Chemical analysis of treated and control samples revealed that pH, salt percentage, TVB-N content decreased significantly (p <0.05), and acidity increased significantly (p <0.05) in treated samples compared to control samples. Also inoculate starter culture (Lactobacillus plantarum and Paenibacillus polymyxa)reduced the amount of histamine content to about 0.347 and 0.326 mg mL-1 from 0.473 and 0.368 mg mL-1 in control and treated samples, respectively. Results of microbial evaluation revealed that populations of Halophiles, Enterobacteriaceae and fungi decreased significantly in treated samples compared to those of control samples (p <0.05), but colony populations of Bacillus andLABincreased significantly in treated samples compared to those of control samples (p <0.05). In general, addition of starter culturehad a positive effect in reducing the amount of histamine and improving other chemical properties and microbial quality of the fermented fish sauce.