We conducted a systematic review of the literature from 1965-1994 to assess the value of history and physical examination in the diagnosis of sciatica due to disc herniation; we also included population characteristics and features of the study design affecting diagnostic value. Studies on the diagnostic value of history and physical examination in the diagnosis of sciatica due to disc herniation are subject to important biases, and information on numerous signs and symptoms is scarce or absent. Our search revealed 37 studies meeting the selection criteria; these were systematically and independently read by three readers to determine diagnostic test properties using a standard scoring list to determine the methodological quality of the diagnostic information. A meta-analysis was performed when study results allowed statistical pooling. Few studies investigated the value of the history. Pain distribution seemed to be the only useful history item. Of the physical examination signs the straight leg raising test was the only sign consistently reported to be sensitive for sciatica due to disc herniation. However, the sensitivity values varied greatly, the pooled sensitivity and specificity values being 0.85 and 0.52, respectively. The crossed straight leg raising test was the only sign shown to be specific; the pooled sensitivity and specificity values were 0.30 and 0.84, respectively. There was considerable disagreement on the specificity of the other neurological signs (paresis, sensory loss, reflex loss). Several types of bias and other methodological drawbacks were encountered in the studies limiting the validity of the study results. As a result of these drawbacks it is probable that test sensitivity was overestimated and test specificity underestimated.