The foremost important aim of the present study was to scrutinize some physiological factors and histopathological conditions in lungs of Baladi and Shami goat^'s kids and its effects on mortality rate during neonatal period. The current study was launched at Ras Sudr Research Station, located at South Sinai, belonging to Desert Researcher Center. Cairo, Egypt. Twenty five adult does of each breed (average 18 months old) were used in breeding season. All does were estrus synchronized and naturally mated. The obtained kids were kept with their mother during the entire experimental period (one month from February to March 2017) and fed only with colostrum and maternal milk. Kids' live body weight changes, colostrum composition and its immunoglobulin M (IgM) content, daily milk yield and composition, total serum protein and its fractions in both dams and their offspring's were estimated. Dead kids were dissected immediately and lungs were collected for histopathological examinations.The overall mortality rate was significantly affected by the breed and recorded 23.07 % and 56.45% in Baladi and Shami kids respectively. Mortality rate was significantly higher in male than female kids. The level of IgM was higher (P<0.01) in colostrum of Baladi than in Shami does. However, Shami does gave higher (P<0.001) milk yield. Goat breed had no significant effect on percentage of milk content of protein, ash, solid not fat (SNF) or total solids (pg/ml), while milk fat (%) and lactose (%) were higher (P<0.001) in Baladi goats milk. Blood serum of Baladi does showed higher values of total protein, albumin, alpha-2 globulins, gamma globulins and A/G ratio, but lower values of alpha-1 and beta globulins in comparison with that of Shami does. For kids, serum total protein, albumin, alpha-1 globulins, beta globulins and A/G ratio were higher (P<0.001), while alpha-2 globulins and gamma globulins were lower (P<0.01) in Shami than Baladi kids. In both breeds, all these parameters increased (P<0.01) after 21 days of parturition with the exception of gamma-globulins which decreased significantly during neonatal period.The lung lesions were grossly recorded 85.71% in dead kids. Histopathologically, broncho-pneumonia, bronchoectasia, emphysema of lung and pneumonia were recorded.It could be concluded that exposure of neonates to cold stress (hypothermia) that was prevailing during experimental period induced a significant increase in the incidence of pneumonia which greatly resulted in kid's mortality. The higher mortality rate of Shami kids might be related to the lower IgM level in colostrum of their dams.