In developing a vaccine against \ud Rhipicephalus \ud appendiculatus, \ud an \ud important tick ectoparasite of \ud livestock in \ud Africa, \ud a necessary \ud first step is identification of \ud antigens \ud which \ud give \ud protective \ud immunity. Antigen profiles of extracts of \ud unfed \ud immature \ud and \ud adult Rh. appendiculatus ticks and \ud their fractions \ud were \ud compared \ud by immunoblotting with sera raised \ud against \ud tick infestation and \ud against \ud whole or fractionated extracts. \ud Several \ud antigens \ud (51.5, 40, 36.5 \ud and 23kDa) were observed \ud to \ud be \ud absent \ud in \ud extracts \ud of \ud fed \ud or \ud partially fed adult ticks. Antigens \ud of \ud 84, 60 \ud and \ud 40kDa \ud were \ud consistently detected in \ud extract \ud fractions \ud shown \ud in \ud immunisation/tick challenge experiments \ud to \ud be immunogenic. \ud The \ud 60kDa antigen was found both in \ud soluble and membrane \ud fractions, \ud whilst the 84 and 40kDa antigens \ud did \ud not appear \ud to \ud be \ud membrane \ud associated. The 84 and \ud 40kDa \ud species \ud appeared \ud heavily \ud glycosylated with a broad range \ud of carbohydrate \ud moieties \ud being \ud present. The 60kDa antigen \ud did \ud not \ud bind \ud significantly \ud to \ud any of \ud the lectins used, suggesting only \ud minimal \ud glycosylation. \ud Probing \ud extracts of unfed larval ticks \ud of \ud different \ud species with serum \ud raised against an immunogenic fraction \ud of \ud Rh. appendiculatus \ud unfed nymphal extract revealed \ud 60kDa \ud antigen \ud species \ud in \ud each \ud of \ud the five different tick species. Immunostaining \ud of sections of \ud unfed adult female Rh. appendiculatus \ud illustrated \ud marked \ud differences in the distribution of antigens \ud associated \ud with adult \ud tick feed and those associated with \ud immunisation \ud with \ud extracts \ud of unfed nymphal ticks and their fractions. \ud Of the \ud unfed \ud immature \ud Rh. appendiculatus extract \ud fractions \ud used \ud in immunisation \ud and \ud adult tick challenge feed experiments \ud in \ud guinea \ud pigs, \ud SEHPLC \ud fraction 2 and the 45% ammonium sulphate supernate \ud fraction \ud were \ud found to be the most protective. \ud The \ud prospects \ud for \ud developing \ud an \ud anti-Rh. appendiculatus vaccine are \ud discussed, \ud and antigen purification strategies are suggested.