A system for controlling the correct arrangement of substitution balls in a football field during a football match, comprising: - a plurality of ball supports arranged in established positions outside a football field, wherein each ball support comprises: a supporting base prepared to secure a substitution football, the supporting base having a cavity or hole made in the upper portion thereof and prepared to partially house the substitution football; a power source; presence sensor means configured to detect the presence of a substitution football in the ball support, the presence sensor means comprising at least one barrier sensor located in the contour of the cavity or hole of the supporting base; wireless communication means; data processing means configured to receive information coming from the presence sensor means and wirelessly communicate, through the wireless communication means, information regarding the presence of the substitution football in the ball support to a central control unit; - a central control unit, comprising: wireless communication means configured to receive the substitution football presence information sent by each ball support; a processor, configured to monitor the presence of a substitution football in each ball support using the received presence information and repeatedly send, wirelessly, through the wireless communication means, the results from the monitoring to a portable electronic device; - the portable electronic device, comprising a processor, a wireless communication module and a screen, the processor being configured to receive, through the wireless communication module, the results from the monitoring and graphically show on the screen the presence or absence of substitution footballs in the corresponding ball supports. - a plurality of ball supports arranged in established positions outside a football field, wherein each ball support comprises: a supporting base prepared to secure a substitution football, the supporting base having a cavity or hole made in the upper portion thereof and prepared to partially house the substitution football; a power source; presence sensor means configured to detect the presence of a substitution football in the ball support, the presence sensor means comprising at least one barrier sensor located in the contour of the cavity or hole of the supporting base; wireless communication means; data processing means configured to receive information coming from the presence sensor means and wirelessly communicate, through the wireless communication means, information regarding the presence of the substitution football in the ball support to a central control unit; a supporting base prepared to secure a substitution football, the supporting base having a cavity or hole made in the upper portion thereof and prepared to partially house the substitution football; a power source; presence sensor means configured to detect the presence of a substitution football in the ball support, the presence sensor means comprising at least one barrier sensor located in the contour of the cavity or hole of the supporting base; wireless communication means; data processing means configured to receive information coming from the presence sensor means and wirelessly communicate, through the wireless communication means, information regarding the presence of the substitution football in the ball support to a central control unit; - a central control unit, comprising: wireless communication means configured to receive the substitution football presence information sent by each ball support; a processor, configured to monitor the presence of a substitution football in each ball support using the received presence information and repeatedly send, wirelessly, through the wireless communication means, the results from the monitoring to a portable electronic device; wireless communication means configured to receive the substitution football presence information sent by each ball support; a processor, configured to monitor the presence of a substitution football in each ball support using the received presence information and repeatedly send, wirelessly, through the wireless communication means, the results from the monitoring to a portable electronic device; - the portable electronic device, comprising a processor, a wireless communication module and a screen, the processor being configured to receive, through the wireless communication module, the results from the monitoring and graphically show on the screen the presence or absence of substitution footballs in the corresponding ball supports.