The present invention relates to a coffee machine for producing and dispensing coffee-based beverages comprising a hydraulic pump (35), at least one dispensing device (13) comprising a filter unit (31) apt to contain ground coffee and a supply unit (14) apt to supply water to the filter unit when the filter unit is engaged with the supply unit and a hydraulic circuit which brings the hydraulic pump into fluid communication with the supply unit of the dispensing device, the hydraulic circuit comprising a supply duct (11) which supplies hot water under pressure to the supply unit, characterized in that it further comprises a system for controlling the dispensing pressure which comprises a control unit (22), a pressure sensor (21) disposed along the hydraulic circuit and apt to generate a control signal representative of the pressure detected, the pressure sensor being electronically connected to a control unit to detect the dispensing pressure, and a hydraulic variable-flow valve (36) disposed along the hydraulic circuit and apt to supply variable quantities of water to at least one dispensing device, the variable-flow valve being actuated by an electronic drive controlled electronically by the control unit in order to regulate the flow rate of water output as a function of a detected dispensing pressure value.The invention relates, moreover, to a method for controlling the dispensing pressure in a coffee machine.