Introduction For the forensic anthropologists, bone remains encapsulate many features of the individual’s life history. The study of post-mortem alteration of bone is needed to differentiate the diagenetic processes from the physiological or pathological processes. The bone diagenesis is defined as all interactions that occur between the bone and the burial environment [1]. Diagenetic mechanisms are complex especially in the early stages because numerous processes take place which depend on the burial environment (weather, soil, scavengers, …). Numerous studies focused on the evaluation of the diagenetic processes over archaeological periods, but few focused over forensic period [2]. Purpose The aim of this study is to evaluate the molecular alterations induced by diagenesis on human bone during 12 months using Raman microspectroscopy. Methods Six ribs from 6 subjects were placed in burial environment which consists in a plastic bin filled with clay soil from north of France. Plastic bins were placed outside and sheltered. Each month, a bone slice (<5 mm) was sampled from each rib. The remaining ribs are placed back in their burial environment. This procedure was repeated each month during 12 months. The bone slices were analysed on Raman microscope LabRAM (HR800) and equipped with a 785 nm laser diode. Forty spectra were acquired per rib and per month. The composition was assessed by 5 physico-chemical parameters calculated from Raman spectra. Results The mineral/organic ratio and the carbonation type-B are decreased at a rate of -0.02 (p=0.015) and -0.03×10-3 (p<0.001) per month, respectively. The crystallinity is increased at a rate of +0.04×10-3 (p<0.001) per month. The modifications observed in the mineral matrix were in agreement with previous studies. The hydroxyproline/proline ratio is not modified. The collagen cross-links are decreased at the rate of -0.012 (p < 0.001) per month. The collagen cross-links give an assessment of the bonds that contribute to the stabilization of the helicoidal structure of collagen fibrils. This finding is in agreement with the mathematical simulation of the collagen hydrolysis [3]. Conclusion In our conditions, the mechanism of diagenesis is driven by the hydrolysis of the collagen for bone remains buried during 12 months. References: [1] R.E.M. Hedges, Archaeometry, 44 (2002) 319 [2] N. Procopio, C.A. Mein, S. Starace, A. Bonicelli, A. Williams, Biology, 10 (2021). [3] M.J. Collins, M.S. Riley, A.M. Child, G. Turner-Walker, J. Archaeol.Science, 22 (1995)