This work presents a novel meta-analysis for methane yields from anaerobically digesting dairy cattle manure. A database is compiled from 115 articles (2181 cases) by systematically assessing the academic literature. Y-CH4 and secondary variables collected in the database describe performance, operation conditions of digester and manure composition. Inputs to the database are normalised to enable interstudy uni- and multi-variate analysis, according to different types of digesters. Most cases (N = 1299) are reported for batch digesters and meta-analysis results in a mean Y-CH4 of 0.230 +/- 0.016 m(3)kg(-1). CSTR (N = 241), results in mean of 0.190 +/- 0.016 m(3)kg(-1) (random-effect model). Other continuous digesters, such as fixed-film, plug-flow and UASB require further cases for the application of meta-analysis. For non-specified semi-continuous digesters (N = 347), the mean calculated by the random-effect model is 0.204 +/- 0.032 m(3)kg(-1) (N = 27). With respect to multi-variate analysis of operation conditions, batch digesters form four clusters, while two clusters are identified for CSTR and three for semi-continuous digesters. For variables describing manure composition, batch digesters present eight clusters, while CSTR and semi-continuous digesters have insufficient cases. The strongest correlations found for these secondary variables (Spearman's rho: -0.685 and -0.696) result for pH and Y-CH4 in batch and CSTR, respectively. Maximum Y-CH4 estimated by meta-analysis are proposed to replace the default IPCC values because they are based on a larger sample size and integrate updated literature. In particular, markedly higher Y-CH4 are obtained for Asia, Middle East and Indian Subcontinent than those in the IPCC guidelines. (C) 2016 Elsevier Ltd. All rights reserved.