Biomarker research has become increasingly interesting in many areas nowadays. Biomarkers are indicators of the biological process that can show changes in disease and health status and reveal pathological conditions. There is always a need for markers that divide patients into risk categories that can help in early diagnosis, detect complications ahead of time, guide treatment, and predict adverse outcomes in a chronic complex and certain diseases such as cancer. microRNAs (miRNAs) are ~ 22 nt long npcRNAs involved in post-transcriptional arrangements. miRNAs regulate messenger RNAs (mRNA), especially through negative regulation of gene expression. The fact that miRNAs have come to the fore in many disease mechanisms brings up their use as biomarkers in the early stage. The purpose of this review is to gather the latest information on this subject by bringing together recent articles and reviews to contribute to understanding the role of miRNAs, which act as biomarkers in different ways in vital processes, in the formation, early diagnosis, and treatment of diseases. miRNAs have an important potential to become a next-generation biomarker and therapeutic. But, each miRNA molecule can bind to a large number of different mRNAs, and different miRNAs in each mRNA. Therefore, new findings are needed to determine the expression activities and targets of miRNAs.