This study was designed to evaluate the association of extenders and cryoprotectants on the sperm head morphometry of Pirapitinga (Piaractus brachypomus) after thawing compared to fresh semen. Thirty Pirapitinga males were hypophysed 14 hours before semen collection. One aliquot of each seminal sample valid was fixed for morphometric analysis and the remainder formed the pool which was divided into three parts. The first part was frozen in PCW-104 or Ringer added 10% of Dimethyl sulfoxide (DMSO) or 10% of methylglycol (MG) with a dilution rate of 1:4 or 1:6 (semen: extender) and filled into 0.50 mL straws. The second, together with individual samples from each animal, was fixed for subsequent morphometric analysis. The third was transported to the laboratory in styrofoam at 4 ° C for analysis of objective motility post-activation. All analysis was carried out using the software Sperm Class Analyzer. After 45 days, the straws were thawed and sperm were assessed for motility and morphology. The data were submitted to ANOVA and motility was compared using the Kruskal-Wallis. Morphometric data were compared between treatments using the SNK test and the control by Dunnett test (p<0.05), expressed as mean and standard deviation. After thawing, all treatments had significantly lower motility compared to the control, and the samples preserved in PCW-104 had significantly higher motility compared to those preserved in Ringer (p<0.05). Related to sperm head morphometry of fresh semen, the means values were: length 3.3784±0.132μm, width 0.075±2.3391μm, area 0.386±7.3130μm 2 , perimeter 9.7249±0.332μm, elongation 0.1843±0.018, ellipticity 0.055±1.4592, regularity 0.8536±0.009 and roughness 0.9589±0.027. After cryopreservation, there was no influence of dilution rate used in any of the parameters evaluated, in addition, the samples preserved in Ringer showed area, perimeter, length and width similar to control. There were also no significant differences in the effects on the variables regularly and roughness (p> 0.05). The samples cryopreserved in PCW104 had significantly higher measures of length and perimeter that preserved in Ringer (p<0.05). Respect to the width and consequently the area, samples cryopreserved in PCW-104 were significantly superior to the control measures and to the samples preserved in Ringer (p<0.05). There was a significant reduction in the ellipticity and elongation in all treatments after thawing as compared to control (p<0.05). In addition, samples cryopreserved in PCW-104 showed a significant reduction of these two parameters compared to samples preserved in Ringer (p<0.05). It can be conclude that, with a better sperm motility and greatest change in head after thawing, probably, cryopreservation in PCW-104 made the sperm more adapted to survive in unfavorable conditions. This study was approved by CEUA (Ethics Committee for Animal Use of the Ceará State University) with protocol number 09230730-2. Keywords: Fish. Semen. Computer-assisted Semen Analysis.