This study was done to evaluate and study the decaying curve of IBD MDAbs of the native chicken breeds including (Fayoumi, Dandrawi, Senawi and Baladi) were taken in consideration as compared with (Lohmann white) layer type breed. The results showed that the decline of maternal immunity of IBDV in Lohmann is the faster followed by Senawi, Baladi, Fayoumi and Dandrawi and the 1 day IBD ELISA titers were shown to be nearly equal in Senawi (5449 ± 371) and Lohmann (4536±437) and titer of Baladi chicks was close to the for mentioned two breeds (5327±371), the Dandrawi (4649±331) and Fayoumi (4596±857) are lower but close to each other. The standard deviation (SD) values recorded in Fayoumi breed showed great variation in the recorded titers, while of the other 4 groups seamed to be homogenous. Comparing the 22 day decline manner in titer it was clear that the loss in titer in Fayoumi (3494) and Lohmann (3413) was nearly equal and followed by Dandrawi (3093) and Baladi (2972) those showing lower titers. The recorded unprotected titer ≤ 400 was detected at 43 days in Lohmann, Baladi and Senawi, 37 days in Dandrawi and 31 in Fayoumi. Percentage of decline from its original values showed that Fayoumi last (75.95%) at 22 days followed by (66.53%) in Dandrawi followed by (62.78%) Lohmann,(55.79) Baladi and (55.19) Senawi. Different breeds showed different slope values that indicate differences in the decay of maternal antibodies. The predication of antibody titer for each breed as the slope in decline curve in Lohmann chicks showed highest values followed by Dandrawi chicks while the Fayoumi and Baladi were as the same values and on the other hand the Senawi showed the lowest value.