Two analogs of the red pigment‐concentrating hormone (RPCH) have been synthesized by the solid‐phase method: [Thr6]‐RPCH (I) and [Tyr4, Thr6]‐RCPH (II). Analog I has the same amino acid composition as the second adipokinetic hormone (AKH‐II) isolated from locust corpora cardiaca. Bioassay for lipid‐mobilizing activity in adult male locusts gave the following increases in hemolymph lipid content: AKH‐I, 3.5; I, 2.4; II, 2.9. The biological response shown by I lends support to the conclusion that its sequence is that of the presumptive AKH‐II. Replacement of Phe in position 4 by Tyr does not reduce the adipok