Introduction: Nocardia spp are widely distributed group of actinomycetes that occur  in a wide   range  of  manmade and natural habitat  including  activated  sewage  sludge, soil, water  and  tissues  of  plants  and  animals including human. Nocardia causes many diseases, notably pulmonary infections in man and mastitis in animals.
Methods: The study subjects included 300 milk samples and 20 soil samples from different farms in Khartoum State, which include Hilat Koko, Ghandahar, Al Silate and Almuaileh. Distribution of the enrolled milk samples was as follows; 100 from goats, 100 from cows and 100 from sheep. Soil samples distribution was as follows; All target samples were cultured on TSA and GYEA and then Gram's stain and different biochemical tests were used for further identification. Finally, PCR targeting 16Sr RNA gene was carried out for all Nocardia isolates.
Results: Dairy animals included in the present study were found to be infected with Nocardia species with different ratio; goats 13/87 (14.9%%), cows 11/77 (14.2%) and sheep 0/60 (0%). Other pathogenic bacteria were also identified in milk, these included Streptococcus, Dietzia,  Rhodococcus  and   Mycobacteria.
Our findings proved also the existence of  Nocardia spp. among 35% (7/20) of the soil samples, three samples isolated from farms of  Hilat Koko, one sample from Ghandahar, two samples from Al Silate and one samples from Al muaileh.
Conclusion
In the present study, the Nocardia species were isolated and identified from the soil and milk samples of dairy animals of the same farms by conventional and molecular methods. This finding strongly suggest that soil could be the possible source for the infection of farm animals.