The use of animals in toxicological screening is a controversial issue. The Draize eye irritation test receives particular criticism because of the injuries inflicted on the test animals. In recent years various in vitro methods have been developed to replace the heavily criticised Draize rabbit eye test for irritation testing. One of the best-studied alternative methods is the Hen's Egg Test-Chorioallantoic Membrane (HET-CAM). In the present studies comparative screening was performed with a set of pesticides to establish parallel data on in vitro (HET-CAM) and in vivo (Draize) results. The tested pesticides included Arelon 500 FW (isoproturon), Banvel 480 (dicamba), Dikamin D (2.4 D), Karathane LC (dinocap), Ronstar (oxadiazon) and Modown 4 F (bifenox). In most cases a good correlation was found between the HET-CAM assessment and results of the Draize rabbit eye test. Although the current form of the HET-CAM test is a valuable prescreen method for predicting the ocular irritation potential of chemicals, and can be used for reducing the number of experimental animals, a number of technical problems must still be addressed before these systems can replace whole animal tests. The HET-CAM test can be a useful component of a battery of tests needed for replacing the Draize rabbit eye test.