Usage of chemical fertilizers in rice cultivation becoming threatens to the ecosystems of the world. Bio-fertilizer is one of the alternative sources in the rice cultivation with less harm to the human and environment. An experiment was conducted at the Rice Research Station, Sammanthurai, Sri Lanka during ‘Yala’ 2017 to evaluate the possibility of replacing the chemical fertilizers with bio-fertilizers in the production of rice. Bio-fertilizer consisted of Azotobacter chrocooccum, Azospirillum bresilensis, Bacillus polimixa, Bacillus megaterium and other Bacillus spp. in a liquid base medium was used for this study. The experiment was laid out in Randomized Complete Block Design with five treatments and four replications. The treatments were T1 - No any fertilizers (Control), T2 – 100% chemical fertilizer, T3 – 50% chemical + 50% bio-fertilizers, T4 – 50% bio-fertilizer, T5 – 100% bio-fertilizer.  Rice cultivar ‘Bg 250' seedlings were transplanted in plastic pots at 12 days old. Bio-fertilizer was prepared for application by mixing with cow dung and cow urine. Prepared bio-fertilizer was applied in the late evening and water was stagnated inside the plastic pots. Combine application of 50% chemical and 50% bio-fertilizer has given the highest values in panicle length (21cm), 1000 grain weight (25.2g), yield (2.5tha-1) and the highest amount of unfilled grains were obtained in the control treatment (29). Lowest values of panicle length, 1000 grain weight, yield was found in no fertilizer treatment (Control). The lowest amount of unfilled grains were found in where the treatment received 100% bio-fertilizer. Based on these results it was concluded that the combined application of 50% chemical and 50% bio-fertilizers has produced the better performances with regard to panicle length, 1000 grain weight and yield in the rice cultivar ‘Bg 250'. It could, therefore, be stated that bio-fertilizer in combination with chemical fertilizer could be used as an alternative way in the production of rice to boost the yield with reduced hazards to human health and environment.