There is a need for cancer-specific tools to evaluate loneliness and cancer-related negative social expectations before developing interventions for cancer patients. The purpose of this study was to examine the reliability and validity of the Cancer Loneliness and the Cancer-related Negative Social Expectations Scale. Data were collected from 300 cancer patients registered to an oncology outpatient clinic of a University Hospital for this methodological study. In the data collection, Patient Information Form, Cancer Loneliness Scale and Cancer-related Negative Social Expectations Scale and the General Loneliness Scale were used. The Cronbach's Alpha coefficient of the Cancer Loneliness Scale was found to be 0.88, Spearman-Brown correlation value was found to be 0.81, CFI, 0.98, GFI, 0.96, X[superscript 2]/SD, 2.99 and RMSEA 0.08. As for the Negative Social Expectations Scale, Cronbach alpha value was found as 0.82, Spearman-Brown correlation value 0.86, CFI 1.00, GFI 1.00, X[superscript 2]/SD 1.33 and RMSEA 0.02. The study revealed those both scales were highly reliable and indices of fit showed perfect fit. These scales are highly valid and reliable instruments for the Turkish society.