The failure to attend to scheduled appointments (no-show) has a significant impact on healthcare systems. Despite the growing of scientific research on the factors that influence no-show, there is not a current summary of the state of art in this area, and systematic review covering all medical fields. In order to fill this gap, this dissertation has the intention to conduct a systematic literature review with three goals: (i) to summarize the characteristics of the studies according to methodology, country, clinical specialty, dependents variables, and no-show rates; (ii) to gather and integrate the results of the factors that significantly affect the non-attendance rates; (iii) to compare this analysis with previous researches. The literature indicates that the no-show does not happens randomly, and to understand the characteristics related to missed appointments is important to improve attendance, allowing the use of this information in scheduling practices. Using the Scopus database, 724 articles were reviewed and 105 selected for analysis. The average no-show rate was 23 percent, and it is most common in patients: younger, low socioeconomic level, greater distance from home to the clinic, with public health insurance or no insurance, and attended by less experienced provider. The most significant factors are high lead time and high rates of previously missed appointment.