Direct one-step aminolysis of high free fatty acid containing triglycerides of used cotton seed oil, karanja oil and jatropha oil was investigated using a new heterogeneous catalyst. The catalyst, 2.5-NaOH/CaO, was prepared in nanocrystalline form by using simple wet chemical method. Complete conversion of used cotton seed oil (99%) to fatty alkanolamides has been obtained in 45 min with the prepared catalyst when 5 wt% of catalyst amount and 6: 1 M ratio of diethanolamine/oil were used. The catalyst was equally active for the transesterification reaction of similar feed stocks. The prepared fatty acid alkanolamides was found to improve lubricity of diesel fuel significantly. (C) 2015 Elsevier Ltd. All rights reserved.