The study investigated mathematics cognitive failures as related to mathematics anxiety, gender and performance in calculus among 450 preservice teachers from four public universities in the South West geo-political zone of Nigeria using the quantitative research method within the blueprint of the descriptive survey design. Data collected were analyzed using the descriptive statistics of percentages, mean, and standard deviation and inferential statistics of factor analysis, independent samples t-test, and multiple regression analysis. Findings revealed that mathematics cognitive failure assessed by the mathematics cognitive failures questionnaire was a multi-dimensional construct (lack of concentration, motor function, memory, and distractibility). Mathematics anxiety level differences in cognitive failures in mathematics and performance in calculus among preservice teachers were significant. Cognitive dimension of mathematics anxiety, gender, affective dimension of mathematics anxiety, lack of concentration and motor function dimensions of mathematics cognitive failures made statistically significant contributions to the variance in preservice teachers' performance in calculus. Based on this baseline study, it was thus, recommended that future studies in Nigeria and elsewhere should investigate whether mathematics cognitive failures could be responsible for students' errors committed when solving problems in mathematics.