Tetracycline staining of teeth is a disfiguring condition that has been shown to be receptive to vital tooth bleaching techniques. Objectives: This study compared the tooth whitening effects of Crest Whitestrips (hydrogen peroxide 6%) against Nupro White Gold (carbamide peroxide 15%) night guard bleaching on patients with mild to moderately severe tetracycline staining over a 3 month period. Methods: 26 patients were given instructions on how to use the two bleaching products for 3 months. At monthly intervals, adverse effects were recorded as well as photographs and colourimeter tooth readings using the X-rite Shade Vision system. L*, a* and b* values were derived. Results: There were no unexpected symptoms reported by patients and most resolved by temporarily stopping use of the bleaching agent. Using a T-test, all patients experienced significant whitening of teeth (p<0.001) based on differences in L*, a* and b* data after 3 months. While the mean overall colour change (ΔE) from baseline to three months was greater for the Nupro White Gold whitening agent 10.1 (SD 3.4) than the Whitestrips 8.2 (SD 4.6), there was no significant difference observed (p=0.26). The lightening effect of the Tray system also showed a greater ΔL* 8.7 (SD 3.8) than the Whitestrips ΔL* 5.6 (SD 4.4) however, this was of borderline significance (p=0.067). Examination of the correlation between the effects of bleaching time and tooth whitening effects at 3 months showed a much stronger effect on of the ΔE (r=0.69) for the tray system verses Whitestrips (r=0.4). Conclusion: This study showed that both bleaching products caused significant tooth whitening effect in patients with tetracycline staining over a three month period.