Objectives: To analyze the anthropometric and laboratory levels associated in adults with diabetes on insulin therapy, monitored by Brazilian Primary Health Care. Methods: Cross-sectional study conducted from August 2024 to January 2025 in 17 Basic Health Units. The final sample included 60 adults (≥18 years) with confirmed type 1 or type 2 diabetes, responsible for insulin preparation and self-administration for at least 6 months. Sociodemographic, clinical, anthropometric, and laboratory data (HbA1c, fasting blood glucose, and blood pressure) were collected by trained undergraduate researchers. Normality was tested using the Shapiro-Wilk test, and variables were described using means, SD, 95% CI, and absolute/relative frequencies. One-sample t-tests compared observed means to international clinical targets (p < 0.05). Results: Most of participants had type 2 diabetes (71.7%), diagnosed >10 years ago (54.9%), and 50% did not perform daily self-monitoring of blood glucose. Insulin therapy was long-established with 90% with >1 year of continuous use. Clinical means were significantly higher than recommended targets for HbA1c (mean = 9.08%; 86.7% altered; p < 0.001) and fasting blood glucose (mean = 198.7 mg/dL; 81.7% altered; p < 0.001). Overweight/excess adiposity were frequent (BMI mean = 26.5 ± 4.85; 58.3% altered), and 63.3% had increased waist circumference. Calf and neck circumferences suggested emerging body-composition risk in part of the sample. Conclusions: Adults on established insulin therapy showed persistent glycemic imbalance and a high frequency of clinically anthropometric risk markers. The findings reinforce the need for individualized metabolic monitoring structured PHC interventions to support safe insulin self-administration.