Background & Aim Human platelet lysate (hPL) has long been used as a xeno-free culture supplement to expand different cell types. Its use is currently thriving given its potential therapeutic properties and its increasing importance in a clinical manufacturing context; however, to date, data regarding the stability of HPL solutions is limited. The general chapter Raw materials for the production of cell-based and gene therapy medicinal products (EP 5.2.12), gives examples of the critical quality attributes specific to each class of raw material. The aim of these studies has been to stablish the expiration time of our product in specific storage conditions. Methods, Results & Conclusion Five batches of our clinical grade hPL currently accredited by Spanish Medicine Agency, were selected for stability testing. Cells were culture (with 5%, 10% and 15% hPL) to analysed the stability of the supplemented medium with Hpl at 4 degrees. The two-year stability study has included the following controls: sterility, mycoplasma, adventitious viruses and endotoxin, activity test, pH, PDGF-AB, total proteins, albumin and IgGs. Sterility, mycoplasma, adventitious viruses and endotoxin level were performed after manufacturing (time 0) and after 24 months while activity test, pH level, PDGF-AB, total proteins, albumin and IgGs concentration were determined from each batch immediately after manufacturing (time zero) or after storage at -80 degrees for 6, 12 or 24 months. All the controls were performed according to European Pharmacopoeia if exist or according to approval procedures. No significant differences were observed regarding the proliferation capacity of fibroblasts cultured with 5%, 10% and 15% hPL for at least 40 days, maintaining the activity in culture. All microbiological controls met the acceptance criteria established to the validation at two years. No significant differences were observed in fibroblasts doubling time when we compared hPL solution and FBS at time 0 and after 24 months. PDGF-AB and pH remained stable at −80 degrees. Besides, total proteins, albumin and IgGs neither showed significant changes along 2 years. Here we show that our hPL solution remains stable in the supplemented medium for 40 days at 4 degrees without significant loss of activity and for 2 years at -80 degrees, maintaining its growth promotion activity in cells, pH and PDGF-AB levels, total proteins, albumin and IgGs concentrations, being an attractive alternative to commercial solutions for cell culture in a clinical context.