This study has assessed the effectiveness of agricultural extension workers through the use of six indicators. Simple random sampling technique was used to select 180 farmers and 60 extension workers from 12 Local Government Areas of Delta State. Interview schedule and questionnaire were used to collect data from respondents. On average, farmers have 7 – 12 contacts per year with agricultural extension workers. Age, extent of contact with extension workers, and education level make a significant contribution to farmers' perception on the quality of agricultural extension workers. This study found no significant relationship between adoption level and extent of contact with extension workers. Agricultural message situation is good in terms of purpose, content and treatment but the provision of logistics for field work of extension workers is not sufficient. The study reveals that agricultural extension service in Delta State is not effective. There is no significant difference in the agricultural extension workers' effectiveness in the three agricultural zones of Delta State. For a better coverage of extension cells, more extension workers should be recruited. The Delta State Government should exhibit renewed vigor in properly funding the public agricultural extension service to ensure improved effectiveness.