Although a significant amount of research has been conducted on the initial bond strength characterization of adhesively bonded composite joints (ABCJ's), improvements in procedures for evaluating bond strength durability of these materials and the role of surface preparation will significantly aid in predicting long-term structural integrity for these systems. This study is aimed at evaluating the effect of contamination on durability of ABCJ's via environmental aging and mechanical fatiguing of specimens. Characterization of initial bond strength and durability performance of specimens is conducted using a double cantilever beam test which provides fracture toughness values and the modes of failure. Fracture toughness of baseline specimens that have not been aged is compared with specimens that have been environmentally aged, mechanically fatigued, and specimens that have been exposed to both aging processes. Surface characterization of the specimens prior to bonding is investigated using atomic force microscopy, contact angle measurements, electrochemical sensors and Fourier transform infrared spectroscopy to correlate bond strength with the surface properties. Additionally, a contamination procedure has been investigated in which laminates are exposed to a silicone liquid prior to adhesive bonding. An update of fracture toughness from baseline, aged and contaminated specimens is provided and correlations with bond strength are evaluated.