Approximately 8% of males and 0.4% of females have a congenital colour vision deficiency. Nurseries and primary schools make widespread use of colour in teaching and unrecognised colour deficiency may disadvantage a child. Early detection of colour vision deficits enables appropriate support to be offered. A relatively new colour vision screening test introduced to serve the early-school-age group is the Colour Vision Testing Made Easy (CVTME) test. CVTME uses identification of pseudoisochromatic targets to screen for red–green colour defects and has previously been shown to be both sensitive and specific in identifying colour deficits (Cotter et al. 1999). The aim of the present study was to investigate the testability (ie ability to cooperate with and complete the test) of infants and young children with the CVTME test. The CVTME test was attempted on 98 children aged from 15 months to 6 years (56 male, 42 female). Testing was performed under natural daylight conditions and in accordance with the test instructions. In the present study 75% of children over 3 years of age and 100% of those aged 4 years or more were capable of understanding and cooperating with CVTME testing. The CVTME test is a quick and inexpensive screening tool for colour vision defects and is easy to apply in children as young as 3 years of age.