Much of the refractive power of the human eye is provided by the cornea, and abnormal corneal morphology can result in significant visual impairment. The corneal curvature is important in determining refractive power. Previous studies have shown significant genetic contributions to the variance in anterior corneal curvature (heritability was estimated at 71% in one study, Dirani et al., 2008). The topography of the posterior corneal surface is also important (with changes evident here prior to the anterior cornea in some diseases), and Scheimpflug imaging allows assessment of this. We imaged the corneas of monozygotic (MZ) and dizygotic (DZ) twins to explore genetic contributions to posterior corneal curvature.Scheimpflug corneal imaging was performed using the Oculus Pentacam (Oculus, Wetzlar, Germany). Twins were recruited from the TwinsUK cohort based at St Thomas’ Hospital, London, as part of a wider twin study. Images were excluded if participants had worn contact lenses in the previous week or if they had undergone any corneal surgery or cataract surgery. Poor quality images were also excluded. The mean curvatures of the anterior and posterior corneal surfaces (expressed in dioptres) of the right eye were compared within twin pairs, with correlation coefficients calculated for MZ and DZ twins. Images from 132 twins were included (33 MZ and 33 DZ twin pairs). Mean (SD) age was 60.7 (10.7) years, and was not significantly different between MZ and DZ twins (p = 0.16). 94% of the twins were female (the proportion was the same for MZ and DZ twins). Mean (SD) values for anterior and posterior curvature were 44.0 (1.4) D and -6.36 (0.26) D respectively; differences between MZ and DZ twins were not significant (p = 0.44 and 0.89 respectively). Coefficients for intra-pair correlation for MZ and DZ twins were respectively 0.76 and 0.53 for anterior curvature, and 0.89 and 0.52 for posterior curvature. The difference in correlation coefficients between MZ and DZ twins was found to be very significant for posterior curvature (p = 0.0009).Correlations were higher for MZ and DZ twins, consistent with significant genetic contributions to the overall variation in corneal curvature; the difference was greater for posterior corneal curvature. This is the first study to explore heritability of posterior corneal topography, and our findings indicate that this may be more genetically determined than anterior corneal curvature.