Purpose: The purpose of this study was to establish the influence of communication participants on adoption of Contagious Bovine Pleuropneumonia (CBPP) Vaccine among Arid and Semi-Arid Lands (ASAL) pastoralists in Kenya. Methodology: The study population was pastoralists in Narok South Sub-county. Sample size was 468 respondents inclusive of qualitative and quantitative samples where 440 responded to questionnaire, 24 in focus group discussions, and 4 in key informant interviews. Cross-sectional research design entailing collection of qualitative and quantitative data was used to assess association between variables. Multi stage, purposive, simple random, systematic and stratified sampling techniques were then employed to come up with respondents. Data derived from 468 respondents was analyzed using statistical Package for Social Scientists (SPSS) version 20.0 and presented using regression coefficients and ANOVA. Findings: All respondents engaged in discussions with others before vaccinating cattle against CBPP. This is because as members of social groups, they interacted with each other through networks, a dominant mechanism for diffusion. Within parameters of experts, veterinary officers and agro-veterinary sales people were influential. In the community, family and neighbours were equally influential and among peers were elders and herders. These influencers were effective because of their attributes and social qualities; trustworthiness and credibility, accessibility, knowledgeability, government authority, advised on many issues, related easily with others and were friendly. Unique contribution to theory, practice and policy: Some people have influence over others in CBPP vaccine adoption among ASAL pastoralists. Governments, veterinary researchers, and communication experts need to leverage on them to encourage diffuse of the vaccine. These influencers could also be trained on some basic aspects of disease reporting, control and eradication.