Background: Coconut water is a biological and sterile liquid. It contains a variety of electrolytes, sugars and amino acids. The purpose of this study is to evaluate the effect of concentration and maturity of coconut water on its ability to preserve human PDL cell viability after exposure to dry time of up to 120 minutes using an in vitro cell culture model. Methods: PDL cells were obtained from sound permanent first molars which were cultured in Dulbecco’s Modified Eagle’s Medium (DMEM). Cultures were subjected to 0, 30, 60, 90 and 120 minutes dry periods then incubated with 100 and 50% young and mature coconut water for 45 minutes at room temperature (18-26°C). Untreated cells at 0 and 120 minutes, and cells incubated in DMEM served as controls. PDL cell viability was assessed by MTT assay. Statistical analysis of data was accomplished by using one-way analysis of variance complemented by Tukey test, and the level of significance was 5% (p < 0.05). Results: 100% mature coconut water (MCW) was better than 50% dilutions obtained from mature or young coconuts. However, no significant benefit to the cells was noticed from the addition of the soaking step prior to 30 minutes dry time. Conclusion: Avulsed teeth which are left dry for > 30 minutes may be benefited from soaking in 100% mature coconut water; further studies on simulated avulsion in animal models are needed to verify the above results.