This paper describes two approaches to implementing third-order oscillators. The first approach proposes a third-order oscillator using transconductors and capacitors. They are cascaded as two lossy and one lossless integrator circuit. This approach is a feedback from transconductance gain = 2. This first circuit is based on a basic transconductor with a simple configuration including 16 ransistors, four current sources and three capacitors. The second approach proposes a third-order oscillator using transconductors, capacitors and a transresistor circuit. These are cascaded as lossy integrator circuits and are fedback with voltage gain = 8. This voltage gain can be designed using a transconductor circuit and a transresistor circuit. This second circuit consists of 18 transistors, four current sources and three capacitors. Since both circuits use no resistors, they are suitable for further fabrication. These circuits use a ±3V power supply.