The colloids utilization is indicated in several situations, but not always applicable in equine practice. The objective of this study was to evaluate the use of the equine concentrated albumin solution (diluted to 5%) during fluid therapy in horses with slight to moderate dehydration, making a comparison with fluid therapy only with physiologic saline solution. Two groups of five adult horses, without clinical alterations, were used. Each animal was submitted to the protocol of each experimental group (fluid therapy only with physiologic saline solution; fluid therapy with equine albumin solution and physiologic saline solution). The dehydration was induced with two administrations of furosemide and fasting. During the experimental period, several evaluations were made: weighing; gasometry; total protein; albumin; Na; K; cardiac output; arterial pressure; urea and creatinin, and calculation of the oncotic pressure and plasmatic volume. With the administration of albumin solution, there was difference, although not always statistically demonstrated in the evaluation of the skin turgor, packed cell volume, total protein and albumin, plasmatic Na, arterial pressure, cardiac output, oncotic pressure and plasmatic volume. It was concluded that: the administration of only a small volume of albumin solution is capable of causing effects comparable to the infusion under pressure of half of the calculated volume of physiologic saline solution necessary to rehydrated the animal; at the end of the fluid therapy, the albumin solution leads to higher values of arterial pressure and serum albumin and lower values of total protein, although without statistical difference, than the single administration of physiologic saline solution; at the end of the fluid therapy, with the use of the albumin solution, the skin turgor still indicates the presence of dehydration, the opposite that occurs with the animals when receiving only physiologic saline solution, where the test indicates good hydration in all the horses; the equine concentrated albumin solution is utilizable in fluid therapy in this species, with easy preparation and administration and with no demonstration of deleterial effects.