Purpose: To describe the current properties and capabilities of an open-source hardware and software package that is being developed by many sites internationally with the aim of providing an inexpensive yet flexible platform for low-cost MRI. Methods: This paper describes three different setups from 50 to 360 mT in different settings, all of which used the MaRCoS console for acquiring data, and different types of software interfaces (custombuilt GUI or PulSeq overlay) to acquire the data. Results: Images are presented from both phantoms and in vivo from healthy volunteers to demonstrate the image quality that can be obtained from the MaRCoS hardware/software interfaced to different low-field magnets. Conclusions:The results presented here show that a number of different sequences commonly used in the clinic can be programmed into an open-source system relatively quickly and easily, and can produce good quality images even at this early stage of development. Both the hardware and software will continue to develop, and it is an aim of this paper to encourage other groups to join this international consortium.I. I M ARCOS (Magnetic Resonance Control System) is a low-cost, high-performance console developed to fulfill the requirements of a rapidly expanding low-field Magnetic Resonance Imaging (LF-MRI) community [1]- [3]. LF-MRI is developing as a customizable and affordable complement to standard high-field MRI (> 1 T), which is an expensive medical imaging modality in terms of purchase cost, maintenance, siting and training, and consequently is concentrated in large hospitals in the economically developed world [4]-[8]. In the last few years, LF-MRI has demonstrated its value for point-ofcare imaging [9]-[15], home healthcare [16], quantitative MRI