In this work, the use of Projection Micro Stereolithography (PmSL) to 3D print a micro-optofluidic device for two-phase slug flow detection is presented. For comparison purposes a PDMS based device obtained by casting was also manufactured. The micro-optofluidic device has a microfluidic T-junction with a micro-optical section that consists of two optical fiber insertions used for two-phase slug flow detection. The working principle in the detection is based on a different light transmission correlated to the fluid interfering with the laser beam in a micro-channel section. The 3D printed material is fully characterized in terms of its surface properties and compared to PDMS used for standard construction using a master-slave casting procedure. The two devices were tested after the setup parameters for the detection were optimized using ANOVA for the 3D printed device. The comparisons of the two devices revealed that 3D printed device can be used for two-phase slug flow detection but future research is still need to obtain a 3D printed resin allowing to outperform PDMS.