We show that soil pH is a key factor in selecting distinct phylotypes of methanotrophs in paddy soils. Type II methanotrophs dominated the methane oxidation in low-pH soils, while type I methanotrophs were more active in high-pH soils. This pH-based niche differentiation of active methanotrophs appeared to be independent of nitrogen fertilization, but the inhibition of type II methanotrophic rate in low-pH soils by the fertilization might aggravate the emission of methane from paddy soils.