Background/purpose Diabetes has been on the rise in Africa. This study aimed to estimate for the first time the national prevalence and its correlates of pre-diabetes and diabetes among individuals aged 18-69 years in Zambia. Methods Nationally representative cross-sectional data were analyzed from 3608 persons aged 18-69 years (median age: 31 years) that participated in the "2017 Zambia STEPS survey," with complete blood glucose measurements. Results Results indicate that 8.8% of 18-69 year-olds had pre-diabetes and 7.2% diabetes. In adjusted multinomial logistic regression analysis, rural residence (adjusted relative risk ratio = ARRR: 2.01, 95% confidence interval = CI: 1.40-2.89), and raised total cholesterol (ARRR: 1.78, 95% CI: 1.08-2.94) were positively, and high physical activity (ARRR: 0.57, 95% CI: 0.39-0.83) was negatively associated with pre-diabetes. Being 50-69 years old (ARRR: 3.03, 95% CI: 2.03-4.52), having central obesity (ARRR: 1.90, 95% CI: 1.20-3.03), and hypertension (ARRR: 2.24, 95% CI: 1.61-3.13) were positively associated with diabetes. In addition, in the unadjusted analysis, female sex, lower education, alcohol family problems, and alcohol dependence were associated with pre-diabetes and/or diabetes. Only 8.4% of the study sample reported that they ever had their blood glucose examined by a health care professional. Having had blood glucose measured was higher among women (9.6%) than men (7.2%) were but not significant (p = 0.08). Residents in urban areas (11.8%) had significantly more often their blood glucose ever measured than residents in rural areas (5.4%) (p < 0.001). Among study participants with diabetes, 22.3% were aware, 9.4% were currently taking treatment, and 17.1% had controlled their diabetes (< 7.0 mmol/L). Conclusion Almost one in ten participants had pre-diabetes and diabetes and several associated variables were detected which can aid in designing intervention strategies.