Biohydrogen (H2) production from wastewater using microbial electrolysis cells (MECs) is an environmentally favourable, efficient, and sustainable technique. In MEC, under a nominal external voltage supply, organic constituents present in the wastewater are biodegraded at the anode using electrochemically active microorganisms. The electrons and protons released during bio-oxidation process are transported to the cathodic chamber and subsequently reduced to form H2 at the cathode. Owing to favourable thermodynamic conditions, the H2 yield of MEC is higher than conventional biological processes. In comparison, the electrical energy demand for H2 production in MEC is substantially lower than that required for the commercial water electrolysis. The better yield efficiency and minimal power requirement make the MECs an exciting prospect for sustainable H2 recovery from waste streams. Despite the substantial study, MEC still needs to be adopted on a large scale due to several operational constraints. The critical barriers in commercialising MEC systems include expensive reactor components, microbial competition, and low-grade H2. The current chapter outlines the existing technological complications and elucidates different strategies for addressing these constraints. The chapter also includes insights on pivotal factors that can drive the integration of this H2-producing technology with the mainstream wastewater treatment infrastructure in the future.