Several communications of identificatives data and of health of the patients of a hospital, being the assign the Agency of Public Health, and taking the LOPD and the sectorial regulations into account, are analyzed. In a concrete case brought up, and within the framework of functions eminently epidemiological and statistical, the communication feels fitted out for the sectorial regulations, but requires the anonimització of the data; this, without harm that the regulations can concede to the assign emmarcables functions in the provision of sanitary assistance, or that the consent of the patients is counted. Also the communication of data in relation to notifiable diseases, and the communication of patients data in risk of social exclusion are analyzed. In general thermal baths, the hospital can request to the assign suitable and sufficient information with respect to its request of access to data, and the assign has to specify or justify enough the purpose and the legal habilitation of the communication.