Background: The Language Development Survey (LDS) and the MacArthur-Bates Communicative Development Inventories (MB-CDI) are two parental report forms that have been productive in providing data on early child language during the past 30 years. The instruments have been used both in studies relating to typical developing children and in screening for language difficulties. Aim: To review the evidence for the LDS and the MB-CDI utility as screening instruments. Methods: A literature search in PubMed and PsychInfo identified 16 articles based on LDS or MB-CDI that reported statistics pertinent to early screening for language difficulties. Main Contribution: It was found that most reviewed studies were explorative in nature and tried out different versions of the screening test, including different cut-off values, multiple reference tests, small sample sizes and rarely reported confidence intervals. Spectrum, verification and review biases were common. Moreover, no study could convincingly show that the actual diagnostic accuracy was sufficient for clinical use. Conclusions: There is insufficient evidence that the LDS or any version of the MB-CDI is a valid tool for screening for language difficulties. Of course, this is not to say that sufficient evidence will not be achieved in future studies, or that the instruments do not work well for purposes other than screening.