In this work the open photoacoustic cell technique (OPC) is applied for measuring the thermal diffusivity (alpha) of human nail tips. Human nails are natural polymers that receive less attention in clinical analysis than other human body parts, although they are very interesting in giving information about some external diseases like dystrophies. Diagnosis and therapy with topic application of anti-fungal creams could be monitored since thermal properties are known. The OPC experiments in the low frequency range were done and through photoacoustic signal decay, the OPC model were used for fitting data in order to obtain the thermal diffusivity of the human nail in vitro. The average value for the nail tips used was found to be alpha ˜ (8.9 ± 1.3) × 10-4 cm^2/s, when different light source is used for photothermal heating. This average is of the order of that evaluated for the human skin.