AbstractLubinsky [1986: Am J Med Genet 2:9–16] has defined associations as derivatives of causally nonspecific disruptive events acting on developmental fields. Opitz [1992: Second International Workshop on Fetal Genetic Pathology]considers developmental fields as the basic biologic units of individual development and of evolution, and has stated that associations represent the idiopathic occurrence of multiple congenital anomalies during blastogenesis. These concepts imply that associations represent the concurrence of a greater number of developmental field defects (DFDs) than other patterns of multiple anomalies.The coding system for children with multiple congenital anomalies, developed in the Spanish Collaborative Study of Congenital Malformations (ECEMC), permits analysis of DFDs as morphogenetic units. Thus, we can study their presence in any type of MCA pattern, regardless of its etiology.Here we present the analysis of a selected group of DFDs of blastogenic origin. Specifically, we have studied how the groups of defects, usually comprised in those specifics DFDs, are observed in children who present different clinical entities such as associations, embryopathies, syndromes of known etiology, and others. The results of our analysis show a greater concurrence of the selected DFDs in associations than in other MCA pattern, and support the concept of Lubinsky [1985: Am J Med Genet 21:35–38; 1986] and Opitz [1992]. © 1994 Wiley‐Lis