The drying behaviour of carrot, parsley, red beetroot and onion slices of 5 and 10 mm thickness was investigated in a convective dryer at a drying temperature of 50, 60 and 70 C under natural convection conditions. The experimental drying data of the vegetables slices obtained were fitted to five empirical thin-layer models: Lewis (Newton), Henderson and Pabis, Page, Modified Page, Wang and Singh. The effects of the vegetable species, air drying temperature, and slice thickness on the model parameters were determined. Four statistical tools, namely, the determination coefficient, root mean square error, reduced chi-square, and t-statistic method were applied to determine the fittings. The Page model with the model parameters determined by a summation equation, a square type dependence for the drying air temperature and a rational one for the slice thickness is recommended as the most suitable model (R2= 0.9699, RMSE= 0.0587, χ2= 0.0035, t-stat= 0.6739).