We have conducted a search for neutron emission from cold fusion systems of the electrochemical type and, to a lesser extent, the high‐pressure gas cell type. Using a high‐efficiency well counter and an NE 213 scintillator, the experiments were conducted on the earth’s surface and in a shielded cave approximately 50 ft underground. After approximately 6500 h of counting time, we have obtained no evidence for cold fusion processes leading to neutron production. However, we have observed all three types of neutron data that have been presented as evidence for cold fusion: large positive fluctuations in the neutron counting rate, weak peaks near 2.5 MeV in the neutron energy spectrum, and bursts of up to 140 neutrons in 500‐&mgr;s intervals. The data were obtained under circumstances that clearly show our results to be data encountered as a part of the naturally occurring neutron background, which is due primarily to cosmic rays. Thus, observing these types of data does not, of itself, provide evidence for the existence of cold fusion processes. Artifacts in the data that were due to counter misbehavior were also observed to lead to long‐term ‘‘neutron bursts’’ whose time duration varied from several hours to several days. We conclude that any experiments which attempt to observed neutron emission must include strong steps to ensure that the experiments deal adequately with both cosmic‐ray processes and counter misbehavior.