Additive manufacturing (known as 3-D printing to the public) technologies are capable of fabricatingmechanical parts without the limitation of geometriccomplexity. If properly designed, a mechanism can alsobe automatically fabricated without the need of assembly.Considering these capabilities of 3-D printing, this paperpresents a novel pneumatic robot design that can befabricated by 3-D printing processes without the needof assembly. The key element of the proposed robot isthe innovative design of a pneumatic stepper motor thatallows control of multimotion pattern modes. The proposedpneumatic stepper design is based on a fan motor, thus,having a low requirement on airtightness, which makes itpossible for 3-D printing fabrication. For angular motioncontrol, a roller valve is added to the fan motor design. Bycontrolling the air pressure of the roller valve, continuousmotion and stepping motion can be obtained. Experimentshave shown that the angular velocity can also be controlledby varying the roller-valve air pressure. The effectivenessof the proposed concepts has been demonstrated by a 3-Dprinted nonassembly pneumatic robot. The printed robot,when connected with air tubes and a pneumatic controller,can perform simple pick and place operations. It is arguedthat the future functional nonassembly pneumatic roboticsystems could be 3-D printed for relevant industries.