One of the major advantages of using Pichia pastoris is that it is readily adapted to large-scale culture in bioreactors. Bioreactors allow precise regulation of cell growth parameters increasing both yields and reproducibility of the culture. P. pastoris cultures grow to very high cell densities which helps minimise culture volume and facilitates downstream processing of the sample. Here, we provide protocols for the large-scale production of the human adenosine A2A receptor (A2A R) and provide some details of how bioreactor cultures can be used for optimisation of expression of the human dopamine D2 receptor (D2DR).