Abstract Background: Low birth weight (LBW) is defined as a live born infant weight less than 2500 g regardless of gestational age. The world health organization estimates 25 million LBW babies are born worldwide annually and 95% occur in developing countries. A baby’s birth weight can be affected by the mother’s diet from birth to pregnancy, and her body composition at conception. LBW is the most important hospital concern worldwide and is still one of the leading causes of prenatal and neonatal deaths in Ethiopia. Objective: To assess the association between maternal nutritional status during pregnancy and LBW among mothers who gave birth and visiting Tikur Anbessa Hospital. Methods: A hospital-based unmatched case control study was conducted from October 1/2022 to December 30/2022 in Tikur Anbessa Hospital. 255 sample size was determined using Epi info 7 based on the assumptions 95% level of confidence, 80% power, 2:1 control to case ratio, 6% expected proportion among controls and 19.1% expected proportion among cases. Data was collected by interview using a pretested structured questionnaire and reviewing medical records. Newborns’ birth weight was measured using a standard weight scale and mother’s MUAC using a standard MUAC measuring tape. Data was cleaned and coded using Epi-data 7 and exported to SPSS 26. Variables having P-value < 0.25 in the bivariable model were entered into a multivariable regression model. Adjusted odds ratios were used to identify the association between the dependent and independent variable. Statistical significance was declared at P-value ≤ 0.05. Results: A total of 192 (64 cases and 128 controls) were participated with the repose rate of 75.3%. The Multivariable logistic regression analysis showed a positive association between lower maternal nutritional status indicators and LBW. specifically, MUAC <23 cm [AOR=6.14; 95% CI: (2.17,17.3)], hemoglobin level <11 mg/dl [AOR = 4.58; 95% CI:(1.91,10.9)], absence of Nutritional Counseling [AOR = 2.28; 95% CI: (1.04,4.98)], lack of Iron/ Folic acid supplements [AOR = 6.02; 95% CI: (2.12,17.2)] and no Multiple micronutrient supplements [AOR = 6.44; 95% CI: (2.52,16.5)] were significantly associated with increased risk of low birth weight. Conclusion: this study showed a strong link between maternal nutritional status and LBW delivery. Thus, public health intervention in the field of maternal and child health should be addressed by strengthening multi-sectoral efforts, which improve women’s adherence of iron-folate and multiple micronutrients, routine measurements of maternal MUAC and early detection and treatment of hemoglobin level during ANC visits. Key words: Low Birth Weight, Maternal Nutritional Status, Maternal MUAC, Hemoglobin Level