The study aims to examine the financing profitability optimization as recorded by Sharia Business Unit of Regional Development Banks (RDBs) in Indonesia. The profitability measured by Net Operating Margin (NOM) and predicted variables were tested with the ratio of Operational Cost to Operational Income (BOPO), Non-Performing Financing (NPF) and Profit Sharing Financing (PSF). On the basis of the literature review conducted, the study proposed five path coefficients to impact NOM, of which the constructed direct path to NOM was three and two for indirect paths. Time series data used were obtained from annual reports and publication reports. Using Pearson Correlation and Path Analysis, the study has found that BOPO, PSF, and NPF contributed to impact to NOM directly, and PSF impacted NOM indirectly through BOPO. Interestingly, PSF recorded a negative impact on NOM, suggesting inefficiency matters faced by SBU of RDBs not contributed from PSF. Another interesting finding, NPF was found insignificant to BOPO, indicating loan default is not a major matter for inefficiency issue, but could be a tight financing policy