The area occupied by the Igbo-speaking people of eastern Nigeria ranks high among West Africa's yam producing zones. Whereas the yam is the Igbo food crop par excellence there is nevertheless considerable local variation in local farming practice and land-use systems. This paper describes three farm units in different parts of Igbo country, indicating the role of yam in the cropping system. The material is derived from surveys undertaken in 1977, but in two of the three cases it has been possible to compare the information with similar surveys undertaken by the author in 1964, prior to the Nigerian civil war. Three case-study farms cannot constitute a sample in any statistical sense and no generalization is possible. The material is presented because the profound changes experienced in the last fifteen years ensure that any time series data, however patchy, are of great intrinsic interest, and because it serves to indicate the extent to which land use systems at the micro-level may differ, even though the basic set of crops may be broadly similar. The three farms studied are representative of their ecological zone: the first reflecting conditions in the zone of highest population density and greatest land shortage; the second, in the more open land on the Nsukka plateau, conditions in an area where land shortage is not yet so great as to have obliterated the distinction between intensively farmed compound land and more extensively ‘bush-fallowed’ land; and the third, conditions of relative land-plenty in southern Igboland, where farming systems show marked continuity with conditions before the civil war. The paper stresses the role of yam in the fanning systems concerned, and the subtle interplay of social, economic and ecological factors involved in its continued cultivation.