Glycosaminoglycans (GAG) in gingival crevicular fluid (GCF) samples were determined by cellulose acetate electrophoresis and densitometric scanning. Two GAG bands, hyaluronic acid and chondroitin-4-sulphate (C4S), were detected in GCF from implants, similar to the profile from teeth. High GCF volumes and GAG contents, notably C4S, may reflect postoperative alveolar bone responses, particularly resorption, at different stages of healing and function of successful implants. They may also indicate adverse tissue changes in failing implants. A comparison of crowned implants and matched teeth suggests that the periodontal ligament contributes to the GCF GAG profile. This may be a useful laboratory method of monitoring implants to detect adverse tissue responses at an early stage. Keywords: dental implants, gingival crevicular fluid, glycosaminoglycans, implant monitoring