The characteristics of natural convection of a heat-generating fluid with non-uniform distribution of volumetric heat release have been studied theoretically. The analysis was based on analytical estimates method and numerical simulation. It has been found that under particular conditions the details of volumetric heat release distribution over horizontal cross-sections of the liquid pool do not affect the convectional heat transfer characteristics. The vertical distribution of the horizontal cross-sectional mean value of volumetric heat generation completely determines the distribution of temperature in the bulk as well as the heat flux to the cooled boundary. (C) 2007 Elsevier Ltd. All rights reserved.