The present invention provides methods for the large-scale production of recombinant butyrylcholinesterase fused to human serum albumin in cell culture, and in the milk and/or urine of transgenic mammals. The recombinant butyrylcholinesterase-albumin fusion protein of this invention can be used to treat and/or prevent organophosphate pesticide poisoning, nerve gas poisoning, cocaine intoxication, and succinylcholine-induced apnea.