The effectiveness of two dentine-enamel bonding agents has been investigated in vitro when used together with an unfilled, low viscosity resin in eliminating the microleakage of porcelain laminate veneers. The restoration margins were located below and above the amelocemental junction of extracted maxillary central incisors. The bonded specimens were thermocycled and investigated for microleakage by employing a standard dye penetration technique. Leakage was scored at the cervical and incisal margins. Tenure was found more effective than Creation 3 in 1 in preventing leakage at both the cervical enamel and dentine/composite lute interfaces. With Tenure dentine bonding agent, the leakage observed at the cervical dentine/composite lute interface was found to be similar to that observed at the cervical enamel/composite lute interface. Sealing of finished veneer margins reduced the leakage at all interfaces. © 1991.