<p class="IsiAbstrakInggris"><span lang="EN-GB">Some of the methanotrophic bacteria and N<sub>2</sub>O reducing bacteria have been proven to be able to support the plant growth and increase the productivity of paddy. However effect of the methanotrophic and N<sub>2</sub>O reducing bacteria application as a biofertilizer to indigenous N<sub>2</sub>O reducing bacteria is still not well known yet. The aim of this study was to analyze the diversity of N<sub>2</sub>O reducing bacteria in lowland paddy soil based on a </span><em><span lang="EN-GB">nosZ</span></em><span lang="EN-GB"> gene. Soil samples were taken from lowland paddy soils in Pelabuhan Ratu Sukabumi, West Java, Indonesia. There were two treatments for the paddy field soil, ie. biofertilizer-treated field 20% fertilizer (50 kg/ha) with the addition of biofertilizer and 100% fertilizer. PCR amplification of </span><em><span lang="EN-GB">nosZ </span></em><span lang="EN-GB">gene was successfully conducted using </span><em><span lang="EN-GB">nosZF</span></em><span lang="EN-GB"> and </span><em><span lang="EN-GB">nosZR</span></em><span lang="EN-GB"> primer pair. Denaturing Gradient Gel Electrophoresis (DGGE) process was conducted at 150 V for 5.5h. There were three differences </span><em><span lang="EN-GB">nosZ</span></em><span lang="EN-GB"> bands were sequenced. The phylogenetic analysis showed that they were close to uncultured bacteria. Microbial diversity in the biofertilizer-treated field was higher than that of in the 100% fertilizer-treated field. The biofertilizer treatment has higher in microbial diversity than that of applied non-biofertilizer paddy fields. This research might have impact in the application of biofertilizers due to the emission of N<sub>2</sub>O as a green house gas from paddy fields farming activity. The biofertilizer has great potential application in sustainable environmental friendly agriculture systems.</span></p>