Influence of inherent buffering nature of real field pharmaceutical wastewater (PW) was evaluated in a microbial fuel cell (MFC) at varying organic loads (OL1-OL4). Dynamics of in situ buffers present in the wastewater during remediation enhanced the electrogenic activity. Improvement in power density (PD) and open circuit voltage (OCV) was observed as the organic load increased from OL1 to OL4 (PD of 62.45 to137 mW/m2; OCV-245 to 324 mV). It was concluded from the buffering capacity (β) profiles that base β values were relatively more stable than acid β values indicating the dynamics of nutrients and salts present in PW. pH increased with increase in OL documenting improvement in power output and waste remediation. Present study depicted an optimum pH range suitable for effective operation of MFC for bioelectrogenesis using PW as substrate. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 454-462, 2014 © 2013 American Institute of Chemical Engineers Environ Prog.