Adipose triacylglycerol is mobilised during late pregnancy in humans and rats: the liberated fatty acids are incorporated into very low density lipoprotein (VLDL) by the liver and secreted into the blood stream. Similar hypertriacylglycerolaemia was also found in late-pregnant sows (Wright et al, 1995). It has been shown that VLDL can be separated into two subfractions by heparin-affinity chromatography. The proportion of VLDL-subfraction 2 (higher affinity for heparin) from pregnant sows was related to piglet mortality. The purpose of this investigation was to extend the study to seek relationships between fat deposition and plasma lipids, VLDL lipids and VLDL-subfractions in growing pigs. As most of the fat deposited in the adipose tissue of neonatal pigs is derived from the plasma lipoprotein, it seemed likely that the rate of fat deposition would be influenced by the concentration and nature of available lipoprotein in the plasma.