diff --git a/src/biomon/models.py b/src/biomon/models.py
index 7885f66..5483e21 100644
--- a/src/biomon/models.py
+++ b/src/biomon/models.py
@@ -117,8 +117,8 @@ class Person(TimestampedAbstractModel):
 class Patient(Person):
     monitoring_place = models.TextField(_(u'Monitoring place'),
             blank=True, null=True)
-    room = models.CharField(_(u'Room'), max_length=512,
-            null=True, blank=True)
+    room = models.OneToOneField('Room', verbose_name = _(u'Room'),
+            null=True, blank=True, on_delete=models.PROTECT)
     emergency_contact = models.TextField(_(u'Emergency contact'),
             null=True, blank=True)
     regular_doctor = models.TextField(_(u'Regular doctor'),
@@ -154,6 +154,20 @@ class Patient(Person):
             return None
 
 
+class Room(TimestampedAbstractModel):
+    number = models.CharField(_(u'Number'), max_length=512, unique=True)
+
+    class Meta:
+        ordering = ['number']
+
+    @property
+    def first_letter(self):
+        return self.number and self.number[0].upper() or ''
+
+    def __unicode__(self):
+        return self.number
+
+
 class MetricCheck(TimestampedAbstractModel):
     patient = models.ForeignKey(Patient, verbose_name=_(u'Patient'))
     date = models.DateField(_(u'Date of check'))