The aim of this study was to compare hydroxyproline (Hyp) and total protein levels both in the gingiva and gingival crevicular fluid (GCF) from juvenile (JP), rapidly progressive (RPP), and adult periodontitis (AP) patients and periodontally healthy controls (C). A total of 60 individuals, 15 from each group, were studied. GCF was obtained before gingival sampling. Clinical measurements were recorded. The gingival samples were harvested by full thickness flap operation from patients and immediately after the extraction of the teeth for orthodontic reasons from controls. The samples were analyzed biochemically. GCF Hyp levels were significantly higher in the AP group than those of the RPP and C groups. The strong positive correlations between gingival and GCF Hyp levels were determined in the disease groups. Total protein levels in both the gingiva and GCF were significantly higher in disease groups. However, the differences between the disease groups were not statistically significant. Correlations between the clinical parameters and Hyp levels in gingiva and GCF were determined. The findings indicate the Hyp and total protein levels both in the gingiva and GCF appeared to be increased in the disease groups. These findings suggest that both the synthesis and degradation of collagen and total protein are elevated in periodontal disease. However, our findings do not support the concept that measurement of either Hyp or total protein levels in gingiva or GCF is a suitable or reliable criterion in determination of disease activity.