The effect of salinity types (chloride and sulphate dominated) and levels (4-16 dS m-1) on germination and early growth characters was studied in Acacia nilotica (L.) Willd., an important timber tree of semi-arid zone. Salinity of both the types significantly inhibited germination and growth in Acacia nilotica. However, chloride dominated salinity was found to be more deleterious. The germination percent decreased to half at lowest (4 dS m-1) level of chloride dominated salinity. At 16 dS m-1, the decrease was 90 percent. Similarly, the growth characters such as root, shoot lengths, dry weights at all the stages (i.e. 28 days and 4-12 months) were also affected more in chloride dominated salinity. The decrease in plumule, radicle lengths of seedlings at 4 dS m-1 was 50-60 percent in chloride dominated salinity, whereas in sulphate dominated salinity there was slight increase in these characters at lower level and the decrease was 50 percent at highest level. At later seedling stages (4, 8 and 12 months), the effect of both the types of salinities was less on all of the growth characters. However the chloride dominated salinity caused more reduction even at the lowest level. Hence, in Acacia nilotica salinity of both the types is more deleterious at germination and early seedling stage as compared to later grown stages. The tree species can be successfully used for afforestation programmes on saline wastelands by raising the seedlings in nursery with normal conditions with good soil and water.