OBJECTIVE: The aim of this study was to describe the prevalence of anemia and iron deficiency anemia (IDA) in infants and verify the association of iron deficiency with nutritional status. METHODS: This cross-sectional and observational study included 104 infants aged between 7 and 9 months, assisted from August to September 2021 by the Family Health Strategy program in Sousa municipality (Paraíba, Brazil). Clinical and anthropometric data were collected, and a 24-h food recall questionnaire was applied using the DietPro software (version 5.0) in order to verify food consumption and assess iron intake. Variables associated with iron deficiency (p<0.05) were analyzed using multiple logistic regression. RESULTS: Anemia and IDA were observed in 40.4% and 19.2% of infants, respectively. Only one infant was taking prophylactic supplementation (ferrous sulfate). Infants with IDA presented reduced hemoglobin (p<0.001) and ferritin (p<0.001) and increased Z-scores of body mass index-for-age (Z-BMI) (p=0.027), weight-for-height (p=0.007), and weight-for-age (p=0.032). All Z-scores were inversely correlated with ferritin (Z-BMI [rho: -0.37; p<0.001], weight-for-height [rho: -0.37; p<0.001], and weight-for-age [rho: -0.29; p=0.002]). Ferritin was also directly correlated with daily iron intake (rho: 0.22; p=0.018). Finally, multiple logistic regression showed a significant and direct association of iron deficiency with weight-for-height Z-score (odds ratio: 2.86; 95% confidence interval: 1.38-5.64; p=0.004). CONCLUSION: About 60% of infants presented anemia or IDA. Iron deficiency was associated with the weight-for-height Z-score, showing the vulnerability of infants during the introduction of complementary feeding.