This study determined the impact of staff development on management effectiveness of EEDC Umuahia, Abia State. Having analysed the distributed 104 questionnaire to staff of EEDC Umuahia, Abia State, descriptive survey approach was adopted and analysed using regressions with the help of SPSS version 22.0. The study found that; on-job training / coaching have significant impact on management effectiveness of EEDC Umuahia, Abia State. Secondly, induction/orientation have significant impact on management effectiveness of EEDC Umuahia, Abia State. The study concludes that, on-job-training/coaching and induction/orientation have impacted significantly and positively on management effectiveness of EEDC Umuahia, Abia state as seen. The study recommends that; 1) The management of EEDC Umuahia under study to make it an official policy to ensure that all their workers are been trained/coached, and this should be carried out alongside with modern method of staff development. 2) The management should ensure that only well inducted, orientated qualified staff are been recruited in the system to avoid wastage of funds in training of staff.