Background: The aim of this study was to estimate the prevalence of self-reported lactational mastitis and identify potential factors contributing to the condition among breastfeeding mothers. Methods: This cross-sectional study involved 284 breastfeeding mothers in the first six months of their infants' lives in Al-Ahsa, Eastern Region of Saudi Arabia. The primary outcome of interest was lactational mastitis, which was determined by a self-reported combination of breast symptoms, including redness and swelling and flu-like symptoms, experienced during the six-month period following birth. No minimum symptom duration or predefined combination of symptoms was required for outcome classification. The investigation further sought to identify factors associated with reporting lactational mastitis, using both bivariate and multivariable binary logistic regression analyses. Results: The self-reported prevalence of lactational mastitis was 26.8%, 95% CI ranged between 21.9% and 32.1%. Maternal age was significantly associated with lactational mastitis (p=0.008), with affected women being younger (28.2±5.0 years) than those without lactational mastitis (30.1±6.1 years). A multivariable explanatory model incorporating nipple cracks, breast congestion, and ductal obstruction was significantly associated with lactational mastitis (p<0.05). Nipple cracks were associated with fourfold higher odds of lactational mastitis (AOR = 4.330, 95% CI: 2.142–8.753), while breast congestion was associated with about 11-fold higher odds (AOR = 10.702, 95% CI: 4.970–23.049). Blocked milk ducts were also associated with higher odds of self-reported mastitis (AOR = 2.813, 95% CI: 1.215–6.514) Conclusion: Lactational mastitis is a common postpartum problem affecting over a quarter of breastfeeding mothers in Al-Ahsa. Key detected associated factors, included cracked nipples, breast congestion, and ductal obstruction. These findings emphasize the need for targeted interventions, such as breastfeeding education, proper nipple care, and strategies to prevent and manage breast engorgement.