Introduction: Iodine deficiency disorders (IDD) are a major public health problem for populations throughout the world that affect humans from early foetal life to adulthood. Although IDD can affect any person of any age, pregnant women comprise the most vulnerable high-risk group for IDD. In Sarawak, previous findings from a state-wide IDD study among pregnant women (PW) indicated that PW is at risk of IDD and further assessment is needed. Thus, the study aims to determine the current nutritional iodine status and the impact of universal salt iodization (USI) among pregnant women (PW) in Sarawak. Methods: A total of 30 maternal child health care clinics (MCHCs) were selected using the probability proportional to population size (PPS) sampling technique. It involved four steps: i. listing the clinic to be sampled; ii. writing the population size; iii. cumulating these size measures; iv. Select clinics using the systematic random sample of the required size from the cumulated list. The PW sample size was calculated based on a 95% confidence interval (CI), relative precision of 5%, design effect of 2, anticipated IDD prevalence of 65.0%, and non-response rate of 20%. Thus, the total sample size required was 750 (25 respondents per selected MCHC). The WHO Expanded Programme on Immunization (EPI) survey approach was used to select the first respondent randomly, and subsequent respondents were chosen until the required number of PW was met. The required data were obtained through face-to-face interviews (socio-demographic and food frequency questionnaire), clinical assessments (thyroid size and hyper/hypothyroidism), and biochemical analyses (urine and blood serum). Quality controls were instituted to ensure the collection of high-quality data.