Zn plays a key role in the synthesis and action of insulin. The aim of the present work was to determine whether a poorer Zn status was associated with insulin resistance in a group of 357 Spanish schoolchildren. Zn intake was determined by using a 3 d food record (i.e. Sunday to Tuesday). The body weight, height and waist and hip circumferences of all subjects were recorded and fasting plasma glucose, insulin and Zn concentrations were determined. Insulin resistance was determined using the homoeostasis model assessment (HOMA) marker. Children (11·5 %) with Zn deficiency (serum Zn concentration < 10·7 μmol/l) had higher HOMA values than those with a more satisfactory Zn status (1·73 (sd 0·93)) compared with 1·38 (sd 0·90; P < 0·05). An inverse correlation was found between the HOMA value and the serum Zn concentration (r − 0·149, P < 0·05). The risk of having a greater insulin resistance value (HOMA greater than the 75th percentile) increased with age (OR 1·438; 95 % CI 1·021, 2·027) and BMI (OR 1·448; 95 % CI 1·294, 1·619) and decreased as Zn serum levels increased (OR 0·908; 95 % CI 0·835, 0·987; P < 0·001). Moreover, an inverse relationship was observed between HOMA values and Zn dietary density (r − 0·122), and the Zn intakes of male children with a HOMA value of >3·16 made a significantly smaller contribution to the coverage of those recommended (59·7 (sd 14·7) %) than observed in children with lower HOMA values (73·6 (sd 18·2) %; P < 0·05). Taking into account that Zn intake was below than that recommended in 89·4 % of the children, it would appear that increasing the intake of Zn could improve the health and nutritional status of these children, and thus contribute to diminish problems of insulin resistance.