A resistorless amplifier circuit uses integrated operational transconductance amplifiers to realize a plurality of circuit transfer functions. The preferred embodiment produces an output signal voltage V.sub.out (500) that is either g.sub.m1 /g.sub.m3 or g.sub.m1 /(g.sub.m3 -g.sub.m1) times the input signal voltage V.sub.in (400). Additionally, an alternative embodiment implements a resistorless summing and subtracting operational transconductance amplifier circuit that realizes an output signal voltage as follows: ##EQU1## The resistorless amplifier circuit includes a first operational transconductance amplifier (100) with a transconductance g.sub.m1, a second operational transconductance amplifier (200) with a transconductance g.sub.m2, and a third operational transconductance amplifier (300) with a transconductance g.sub.m3.