Deficits in Joint Attention (JA) may be one of the earliest signs of Autism Spectrum Disorders (ASD). In this longitudinal study we investigated several types of JA behaviors at the age of 24 and 42 months, and their development over time. Eleven children with ASD, 10 children with other developmental disorders, and eight children without a developmental disorder participated. It was found that children with ASD showed significantly less JA at the age of 24 months. At this age, the various types of JA (Basic Joint Attention, Associated Joint Attention, Joint Visual Attention) were correlated with developmental level and number of autistic characteristics. However, at the age of 42 months, these associations were absent. Although children with ASD may show less JA at the age of 24 months compared to other groups of children, by the age of 42 months they reach about the same level of JA, except for joint visual attention. In fact, at both ages, children with ASD differed consistently only on JVA from the other groups. JVA may be a core component of an early screening device for ASD.