In cases of bone critical size defects, a guided bone regeneration (GBR) membrane is used to promote space for bone reconstruction. Calcium phosphates have been widely added to these GBR membranes to increment bioactivity and osteoconduction; however, there is a lack of understanding of their effects on the membranes' properties, other than the biological ones. Therefore, this study developed electrospun membranes of PLGA with additions of HAp (hydroxyapatite):beta-TCP (beta-tricalcium phosphate) in the proportions of 60:40, 70:30 and 85:15 to evaluate the additions' influence. Results have shown, as expected, that the incorporation of calcium phosphates improved osteoblastic size, spreading and migration into the highly porous membranes. Fibre diameters and crystallinity degrees were influenced differently by each phosphate proportion and their characteristics. The group with the lowest HAp:b-TCP ratio (60:40) had a significant difference in the degradation rate faster (aiding in the optimization of the degradation profile) and was the best in terms of osteoblastic behaviour. Additionally, an unprecedented degradation study has shown that the degradation process increased fibre diameters unexpectedly, a behaviour that was detailed and explained. Taken together, results have shown that the calcium phosphates incorporation, if used pointedly, can tune the membranes' properties and the reconstruction of the anatomical bone. (C) 2020 Elsevier Ltd. All rights reserved.