The major whey proteins IgG, serum albumin and α-lactalbumin were purified from camel milk using gel permeation and ion-exchange chromatography. Specific antisera against each of them were raised and used to quantify their heat denaturation in early or mature milk over a range of 60–90 °C for 10–60 min using the single radial immunodiffusion technique. The heat denaturation midpoints for the mature milk heated 30 min were 67·2, 73·0 and 77·5 °C for IgG, albumin and α-lactalbumin respectively. The early milk was more sensitive to heat treatment with coagulation at low temperature and heat denaturation midpoints of 64·8, 71·6 and 72·6 °C respectively. This difference was related to the high IgG content of the early milk (12·6 mg/ml v. 0·5 mg/ml for the mature milk) and stresses the importance of monitoring the IgG level of milk to assess the absence of colostrum.