The potential advantages of ultrashort laser and their use in medicine have been a motivation to understand and control the ablation with laser in femtosecond-picosecond range. This type of laser can be an alternative to traditional method to cut tissues since their can performed very precise incision avoiding damage to surrounding tissues. However, the ablation with fs lasers needs an optimization process in order to reach an ablation rate that permits to realize a surgery in a reasonable time. A complete study of femtosecond laser ablation on bone has been carried out. Ablation threshold has been determined for five different pulse duration, obtaining a decrease of thresholds as pulse duration makes shorter. Single pulse ablation threshold has been obtained by extrapolation yielding a value of 4 J/cm2, slightly higher than those reported by other authors with sample without polish. This is mainly attributed at less water presence in our samples.