The magnetic susceptibility of azurite has been determined in the three principal directions between 1 and 300°K. A transition to the antiferromagnetic state was observed, the Néel temperature being 1.85°K for small external fields. The variation of the transition temperature with field strength is given. Up to H = 17.3 kOe no threshold field was found. To account for an anomaly in the magnetization in the temperature region of liquid hydrogen a coupling scheme is proposed.