Infectious bursal disease (IBD) is a highly contagious and economically importantrnimmunosuppressive viral disease of poultry that is found worldwide. The disease is caused by arndsRNA virus. This study was conducted in National Veterinary Institute from September 2015 tornApril 2015 on the objective of the isolation, identification and molecular characterization ofrninfectious bursal disease virus (IBDV) on infectious bursal disease (IBD) suspected outbreakrnsamples were collected from 2013 to 2015 from different parts in Ethiopia and to test thernimmunogenicity of four different live attenuated commercially available infectious bursal diseasernvaccines and also to select the appropriate infectious bursal disease virus vaccine through thernselected different IBDV vaccine immunogenicity test and cross protection test against the localrnisolated VVIBDV challenge virus and also to determine the appropriate time of IBDV vaccinernadministering time on vaccinated progeny originated chickens. A representative outbreakrnsamples were employed for virus isolation (cell culture) on chicken fibroblast cell (CFC),rnmolecular characterization (touchdown PCR) and PCR positive isolates subjected to furtherrnsequencing. On the other hand the IBDV vaccine immunogenicity test was conducted byrnemployed the four different live attenuated commercially available infectious bursal diseasernvaccines strain: Namely (one mild intermediate strain - D78, one invasive intermediate strain -rnBursine-B2k, and two intermediate plus or hot strain IBD LC75 and IBD EXTREM) andrninfectious bursal disease virus maternal antibody (IBDV MAb) free specific pathogen free (SPF)rnchickens of vaccinated progeny and also the recently local isolated very virulent infectiousrnbursal disease virus (VVIBDV) as a challenge virus. The IBDV MAb was screened thernexperimental SPF chickens before administering the experimental IBDV vaccines. The chickensrnsera was collected and examined post 14 days of primary immunization, post 7 days of boosterrndose or prior to challenge test and also 21 days post challenge test serologically by flock IBDVrnantibody screening ELISA kit to compute the immunogenicity and cross protection capacityrnagainst the challenge locally isolated VVIBDV. Among the study objectives and criteriaâ€™s resultsrnwere revealed as followed, Eighteen (95%) of bursa and four (80%) of the spleen samplesrnsuspensions were grown and develop visible cytopathic effect (CPE) on chicken fibroblast cellrncultures (CEF), totally nineteen cell culture isolates (eleven 2013 and 2014 samples and sevenrn2015 samples) were revealed the expected VP2 gene amplified PCR band (645base pairs); thernxivrneleven 2013 and 2014 positive PCR products sequence analysis were also confirmed therncurrently circulated IBDV were VVIBDV virus. On the other hand based on those computedrnparameters, the IBDV vaccine immunogenicity test studies were revealed that the IBDV vaccinernadministration appropriate scheduled on vaccinated progeny flocks should be at 21 and 35 daysrnage for primary and booster dose vaccination respectively and also the superior immunogenic,rnpotent and efficiently cross protective for recently local isolated VVIBDV was intermediate plusrnIBDV vaccine strain LC75. Therefore based on the above study results the following points werernrecommended producing this candidate live intermediate plus IBDV vaccine strain LC75 shouldrnbe effective to prevent and control the currently circulated VVIBDV virus, commercial poultryrnfarm owners should be screened the IBDV maternal antibody (MAb) of the flock before primaryrnIBDV vaccine administration , and IBDV virus molecular epidemiology study with a plannedrninterval should be conducted to assessed the antigenic diversity of the IBDV virus.rnKey words: Infectious Bursal Disease Virus (IBDV), IBD, IBDV vaccine, polymerasernchain reaction, sequencing, IBDV maternal antibody