Owning to robust, portable, and pump-free design, microfluidic paper analytical devices (μPADs) are increasingly adopted for performing complex multiplex assays in a variety of fields. The current methods for detecting multiple targets in μPADs require patterning the membranes to create hydrophobic barriers, a technique introduced by Martinez et al[1]. Although these barriers created using wax printing, inkjet printing, photolithography, or by chemical modification of paper[2] efficiently utilize membrane surface area and consume less reagent volume, their fabrication requires expensive equipment and skilled personnel, posing a challenge for scale-up. In addition, the generation of non-uniform colorimetric signal due to convection of rehydrated signals create difficulty in signal quantification. To overcome the limitations of traditional μPADs, we have developed a new device called barrier-free μPAD (BF-μPAD) which can detect multiple targets without requiring any physical or chemical membrane modification. The device is fabricated by stacking two paper membranes of different wicking rates. The bottom membrane (called as detection layer) has lesser wicking rate and stores multiple dried reagents. The top membrane (called as distribution layer) has higher wicking rate and acts as a fluid distributor for the bottom membrane. In one embodiment, an 8cm x 2cm device assembly can perform up to 20 different tests in 30 seconds. To demonstrate the multiplexing feature of BF-μPAD, we have selected four salivary analytes; thiocyanate, glucose, nitrite, and protein. Chemistries for their colorimetric detection were deposited on the detection layer and fluid samples containing different concentrations of the analytes were added to the distribution layer. A user only requires a smartphone to visualize and interpret signals, making it a desirable point of care tool at low resource settings. A direct comparison of the limit of detection between conventional μPAD and BF-μPAD shows that BF-μPAD improves the limit of detection by ~3.7x and produces perfectly uniform colorimetric signals. Barrier-free detection in BF-μPAD is enabled by the generation of unique flow patterns, which were modeled in COMSOL Multiphysics using the Richards equation. In contrast to μPADs, large-scale manufacturing of BF-μPADs would only require a commercially available benchtop robotic dispensing system to handle microliter volume, thus significantly reducing fabrication costs and complications.