Solubilities in the system comprising nitromethane and cis-9-octadecenoic acid have been reported in two publications. Hoerr et al.1 studied the solubility of (2) in (1) between 233 K and 393 K by the synthetic method. Schmid, et al.2 determined the upper critical solution temperature also using the synthetic method.At the UCST, the only temperature where direct comparison is possible, the two studies are in rather poor agreement: Hoerr et al.1 (367.7 K) and Schmid et al.2(369.7 K). Accordingly, in the absence of confirmatory studies, all data must be regarded as tentative. However, it may be noted that the UCST values of Schmid et al.2 in well characterized systems are generally lower than other reports. Thus both the UCST values and the other available data1 must be regarded with some scepticism. The tentative numeric data (but see comments above) are given in the following data sheet.