Understanding criminals' personality characteristics could engender appropriate solutions for preventing crimes and treating criminals and the aim of the current work is to predict criminals' (robbers, swindlers and smugglers) personality characteristics by using the Minnesota Multiphasic Personality Inventory (MMPI) in committing type of crime. The research falls under the applied category in terms of goal while in terms of nature it is among surveydescriptive researches. The sample under investigation includes 480 people who were selected by way of classified random sampling method in a systematic form from among the population of criminals in the Central Prison, province of Kermanshah. The tool used in this paper is the Minnesota Multiphasic Personality Inventory (MMPI) (short form of 71 questions). The results obtained from the Minnesota Multiphasic Personality Inventory (MMPI) indicated that prevalence of anti-social personalitycharacteristics and mental weakness among robbers; depression, anti-social personality and schizophrenia among swindlers as well as anti-social traits, mental weakness and schizophrenia among smugglers are seen significantly. Also, the results of the variance analysis demonstrated that there is a significant difference between the (MMPI) clinical scales among three groups of criminals (robbers, swindlers and smugglers) on D scales (depression), Pd (Psychopathy deviation), Pt (Anxiety and psychosis), Sc (Schizophrenia) and Ma (Hypomania) (p<%5). Research findings revealed that criminals enjoy lower level of normal and positive personality dimensions. To sum up, we can infer that all personality characteristics exist in the population of criminals and therapy experts need to pay attention to all sorts of personalities for treating criminals affected with personality disorder.