Experimental data on solid-liquid equilibrium for three cuts in the ternary system acetic acid-propanoic acid-formamide are presented. In the system two adductive compounds exist: 2:1 adduct (CH3COOH)(2)center dot HCONH2 and 1:2 adduct CH3CH2COOH center dot(HCONH2)(2). Liquidus for acetic acid-propanoic acid mole ratios 1:1, 1:3 and 3:1 is given and confronted with liquidus calculated on the basis of binary systems behavior. (c) 2007 Elsevier B.V. All rights reserved.