Abstract: The present invention involves a process for the co-production of ammonia and urea in which two parallel gasifiers are utilized so as to optimize the H2/CO2 ratio in the combined syngas product, thereby maximizing the ammonia and urea production. In a first gasifier, solid and/or liquid hydrocarbon materials are partially oxidized in the presence of an oxygen-rich gas in the presence of a temperature moderator, thereby generating a first synthesis gas mixture comprising carbon monoxide, hydrogen and carbon dioxide. In a second gasifier, natural gas is partially oxidized in the presence of an oxygen-rich gas, thereby generating a first synthesis gas mixture comprising carbon monoxide, hydrogen and carbon dioxide. Because natural gas has a lower C/H ratio than the solid and/or liquid hydrocarbon materials, insufficient CO2 is produced in the natural gas gasifier for urea production when only natural gas is used to produce syngas.