This study presents the combustion and emissions characteristics of Reactivity Controlled Combustion Ignition (RCCI) produced by early port fuel injection (PFI) of low reactivity n-butanol (normal butanol) coupled with in cylinder direct injection (DI) of cottonseed biodiesel in a diesel engine. The combustion and emissions characteristics were investigated at 5.5 bars IMEP at 1400 RPM. The baseline was taken from the combustion and emissions of ULSD# 2 which had an ignition delay of 13 CAD or 1.5 ms. The PFI of n-butanol and DI of cottonseed biodiesel strategy showed a shorter ignition delay of 12 CAD or 1.45 ms, because of the higher CN of biodiesel. The combustion proceeded first by the ignition of the pilot (cottonseed biodiesel) BTDC that produced a premixed combustion phase, followed by the ignition of n-butanol that produced a second spike in heat release at 2 CAD ATDC. The addition of n-butanol into the cycle reduced the compression and peak temperature by 100K and resulted in 35% NOx and 90% soot reduction. Adding 20% cooled EGR further reduced the NOx to a total of 50%. The results suggest that early PFI of n-butanol combined with cottonseed biodiesel resulting in RCCI, may be an effective way of reducing emissions of NOx and soot when compared to the baseline of ULSD# 2.