We evaluated the long-term effect of solvent-borne and waterborne water-repellent preservative pretreatments on the performance of various paint systems applied to different wood substrates. Results were compared to those obtained with untreated substrates. Six substrates were studied: Western redcedar bevel siding, redwood bevel siding, southern pine bevel siding, unprimed hardboard, Douglas-fir plywood, and southern pine plywood. The surfaces of these substrates were either smooth-planed, smooth-sanded, or scratch-sanded. The other variables were the type of paint system (all-latex, all-alkyd, or combined alkyd-latex) and number of paint coats (two or three). After 9 years of outdoor exposure in Madison, Wis., test panels were evaluated for degradation of substrate (checking and cracking) and finish (flaking, cracking, and discoloration), as well as for the presence of decay. The water-repellent preservative treatment helped improve paint performance of substrates with poor paint-holding characteristics; species like southern pine showed the greatest improvement, whether the wood was solid or in the form of plywood. Substrates with good paint-holding characteristics (Western redcedar, redwood, textured hardboard) did not benefit very much from water-repellent preservative pretreatments. Decay occurred in the southern pine test panels. Decay occurred to a lesser extent in panels brush-treated with solvent-borne water-repellent preservative; the water-borne water-repellent preservative was less effective. On the other hand, the paint performance of panels treated with the waterborne preservative was slightly better than that of panels treated with the solvent-borne preservative. Three-coat paint systems (one primer and two topcoats) performed much better than did two-coat systems (one primer and one topcoat). The study also showed that alkyd primer/latex topcoat and all-latex paint systems perform much better than the all-alkyd paint system, with or without water-repellent preservative pretreatments.