The DPP says the charges against the two drivers and three conductors are defective because there is no evidence that any of them had prior knowledge that there was a motive to blow up the buses.
The five were charged at the Makadara Law Courts on Tuesday where they denied the charges, and were released on a bond of Sh5 million each.
The DPP has now directed that the cases be mentioned next week where the charges will be formally withdrawn under Section 87 (a) of the Criminal Procedure Code.
Three people were killed and over 50 others wounded in the twin blasts that occurred on Sunday evening, sending panic in the public transport sector.
The charges against the five and the high bail terms led to protests from PSV operators.