A method for estimation of endurance limits for adhesively-bonded single and single-step double-lap joints was proposed which considers the stress multiaxiality in the adhesive layer. At first, fatigue tests and finite element analysis were conducted for these lap joints. Then, endurance limits of these joints were estimated using their stress distributions and critical regression equations which were obtained from the S-N data of adhesively-bonded scarf-and butterfly-type joints. The results indicate that the endurance limits of these lap joints can be estimated from the regression equation based on the maximum principal stress.