Introduction: Ultrasonographic evaluation of breast is the foremost and appropriate radiological method to evaluate breast disorders in women during pregnancy and lactation. 80% of patients presenting with palpable breast mass during lactation and pregnancy are benign however malignancy must be excluded by a thorough workup. Purpose: The aim of this article was to review different breast pathologies occurring in women during pregnancy and lactation. Methods: A prospective study of one year was done in Dr. Ziauddin University Hospital Karachi. Pregnant or / and lactating females who came for ultrasound breast examination with complain of pain, lump or discharge were included in study. Patients with previous history of incision and drainage, already diagnosed or on medical treatment were excluded from study. Results: A total of 94 patients with an age range of 17- 42 years were included. Right breast was most commonly involved 58.51% than left 41.48%. Ultrasound revealed benign breast diseases in 67.02%, of them most were infective / inflammatory accounting for 55.31%. Malignancy was detected in 7.44% and 25.53% showed no sonographic abnormailty. Breast abscess was the most common breast disease found 25.53% and were more common in lactating 70.83% than pregnant females 29.16%. 9 breast abscesses, 2 galactocele underwent aspiration, mastitis and infected sebaceous cysts were managed conservatively. Trucut needle biopsy done in 6 and FNAC in 2 patients for suspicious looking lesions. Conclusion: Ultrasound is useful in early detection, however, diagnosis is challenging due to changes secondary to hormonal stimulation. A thorough understanding of clinical and imaging features of normal physiological changes and benign or malignant lesions is exigent. Introduction: Ultrasonographic evaluation of breast is the foremost and appropriate radiological method to evaluate breast