In this payer, an attempt has been made to evaluate the convective beat transfer coefficient operating in crop drying in open sun drying conditions (natural convection). Values of the constants, C and n were obtained by linear regression analysis from experimental data obtained for six crops, namely green chillies, green peas, Kabuli chana, onion, potato and cauliflower. Analysis was also performed for Kabuli chana under natural cooling conditions. Based on the values of C and n convective heat transfer coefficients for these crops were determined. The experimental error in terms of percent uncertainty was also calculated. (C) 2000 Elsevier Science Ltd. All rights reserved.