Background: The common causes of 18p deletion syndrome are spontaneous errors in the chromosomal structure in the early stages of human embryonic development. Clinical Presentation and Intervention: In this study, a 29-year-old girl was introduced with the features of deletion of chromosome 18. In addition, GTG banding karyotype revealed that this case had a deletion involving the short arm of chromosome 18. In comparison with the usual phenotype of 18p deletion, many phenotypical features of this case were similar to the other cases of 18p monosomy. Conclusion: However, two new features; difficulty in speaking and persistent limb tremor, were found that had not been observed in previous studies on the 18p deletion. Speaking was without obvious pronunciation, and the patient’s physical movements were always unbalanced. These two features can be new signs for 18p deletion syndrome.