Municipal solid waste (MSW) was vermicomposted in combination with cowdung (CD) using Perionyx ceylanensis for 50 days. The decomposition rate of 55-78% was observed in different vermibed substrates, the highest being CD followed by 10:1 ratio of CD + MSW. The C/N ratio was reduced from 41.8 to 17.6 and 38.8 to 15.4 in MSW + CD (10:1) and CD, respectively. The difference in the final C/N ratio between MSW + CD (10:1) and CD vermicompost was not significant (p < 0.05). The important nutrients, NPK showed significantly (p < 0.05) higher contents in vermicomposts than worm-unworked composts. The degradation rate of cellulose and lignin was 37% and 12%, respectively, in 10:1 vermibed mix with P. ceylanensis. The bacterial, fungal and actinomycetes population in vermicompost was significantly higher than in the compost. The biomass, number and cocoons of P. ceylanensis collected after 50 days showed increase with the increase of CD incorporation in MSW. (C) 2011 Elsevier Ltd. All rights reserved.