The fatty acid composition of Gryllus campestris was analyzed by gas chromatography at successive stages during development and including own eggs. Qualitative analysis revealed the presence of 14 fatty acids (carbon chain length from C12 through C20) in addition to unidentified fatty acids during all stages. There were no differences between fatty acid profiles of eggs, all nymphs, male and female adults. The major components of total fatty acid composition were C16:0, C18:0, C18:1, C18:2 and C18:3. These fatty acids were found to comprise 88-92% of the total fatty acids in all nymphs, male and female adults. The content of C16:0, C18:0, C18:1 and C18:3 decreased in eggs and emerged nymph in contrast; the content of C16:1, C18:2 and C20 fatty acids increased. Certain C20 polyunsaturated fatty acids (PUFA) (C20:2, C20:3 and C20:4) were detected in the nymphs and adults. Decreases were observed in the contents of total saturated and total polyunsaturated fatty acids, but total monosaturated fatty acid content showed an increase as from the first nyrnph stage of both sexes. It is suggested that the fatty acids C16:0, C18:1, C18 and C20 PUAFs are necessary for normal development of G. campestris during their life stages.