The effect of transition element (TE=Cr, Fe, Co, Ni, Cu, Zn) doping on the electronic transport and magnetic properties in the bilayer manganite La 1.4 Sr 1.6 Mn 2 O 7 is studied for the same dopant concentration fixed at 2%. Doping does not cause change in structure but different behavior in magnetic and transport properties. Except for Cr, all the other dopings significantly shift the magnetic transition temperature (T C ) to a lower temperature. Associated with such a decrease, the insulator–metal transition temperature (T IM ) decreases and the peak resistivity (ρp) at T IM increases. Cr doping enhances T C and T IM as well as decreases ρp. Fe doping apparently has a stronger effect than Co and Ni doping. It is also indicated that Cu doping causes an anomalously large increase in ρp. These behaviors are compared with those observed in other bilayer manganites such as La 1.2 Sr 1.8 Mn 2 O 7 as well as in La 0.7 Ca 0.3 Mn 1−x TE x O 3 .