Low-voltage p-type organic transistors with two types of multi-finger source/drain contacts were fabricated on glass and polyethylene naphthalate. They exhibited threshold voltage between −0.3 and −0.5 V and field-effect mobility between 0.2 and 0.4 cm2/ $\text {V}{\cdot} \text {s}$ . Their transconductance in saturation operation varied from ~25 to ~60 $\mu \text{S}$ and scaled with the gate dielectric capacitance and transistor dimensions. All transistors operated beyond 1 kHz, while the transistors with the shortest channel length ( $L = 20 \,\,\mu \text{m}$ and $W = 4.03$ mm) exhibited a cutoff frequency of 13.4 kHz. The transistors were used to build simple voltage amplifiers by adding a resistor $R_{d}$ on the drain side of the transistor. Higher $R_{d}$ required higher supply voltage $V_{\mathrm {dd}}$ but resulted in the increased voltage gain. A voltage gain in excess of 8 V/V was obtained for $V_{\mathrm {dd}}$ of −12 V and $R_{d}$ of 220 $\text{k}\Omega$ when transistor with medium value of transconductance of 37 $\mu \text{S}$ was used. Consequently, the voltage gain of 10 V/V is achievable, making such transistor structures viable for sensor development.