Photoacoustic computed tomography (PACT) has been widely explored for studying human diseases as well as response to therapies. Most PACT systems employ a large footprint, bulky, and high-cost lasers. Light emitting diodes (LEDs) based B-mode photoacoustic imaging systems have emerged as a low cost and compact alternative, offering a unique opportunity to expedite the widespread adoption of photoacoustic imaging in clinical and resource-poor settings. The high pulse repetition rate of LEDs facilitates signal-to-noise ratio improvements through averaging in spite of lower pulse energy. Here, we present the development of first low-cost LED-based PACT system that uses multiple LED arrays and a linear ultrasound transducer to generate three-dimensional structural, functional and molecular images of the object. Similar to OPO based lasers, our LED-PACT system allows for the multi-wavelength photoacoustic imaging vital for mapping functional and molecular information. Our experiments demonstrate that this study will enable clinical and pre-clinical applications such as imaging human arthritis and whole body mouse imaging.