Geoffrey West and colleagues published a series of papers, mostly in Nature, Science and Proceeding of the National Academy of Sciences of the USA, on scaling of different aspects of physiology and life history in organisms as distinct from each other as plants and animals (West, Brown & Enquist 1997, 1999a, b; Gillooly et al. 2001). Recently they even extended their considerations down to cells, mitochondria and respiratory complexes (West, Woodruff & Brown 2002). All these papers invoke the 3/4 scaling of metabolic rate claimed to be derived in their first and basic paper (West et al. 1997; WBE hereafter). It is therefore extremely important to check the legitimacy of their model. First we show that to make WBE's model mathemat-ically consistent either metabolic rate must be directly proportional to body mass (recall that the model is aimed to explain the/4 exponent for metabolic rate) or one of the basic model assumptions, that is, the sizeinvariance of terminal supplying vessels, must be violated. Then we show that animals built according to WBE's model cannot represent a broad range of sizes, because for large animals the volume of blood vessels would exceed body volume. Later we demonstrate that many features of the plant vascular system, insect tracheal system, vertebrate lung or vertebrate cardiovascular system do not conform to WBE's model assumptions. Finally, we argue that 3/4 scaling for metabolic rate is by no means universal, and therefore WBE's model was built to explain a non-existent pattern.