Abstract Amblyomma sculptum ( I xodida: I xodidae) B erlese, 1888 is the most important tick vector in B razil, transmitting the bioagent of the most severe form of spotted fever ( SF ) in part of the C errado (in the states of M inas G erais and S ão P aulo). In another part of the C errado ( C entral‐ W est region of B razil), a milder form of SF has been recorded. However, neither the rickettsia nor the vector involved have been characterized. The aim of the current study was to analyse genetic variation and the presence of rickettsia in A. sculptum in C errado, from silent areas and with the milder form of SF . Samples were subjected to DNA extraction, amplification and sequencing of 12 S r DNA , cytochrome oxidase subunit II and D ‐loop mitochondrial genes (for tick population analyses), and glt A , htr A , omp A and gene D (sca4) genes for rickettsia researches. Exclusive haplotypes with low frequencies, high haplotype diversity and low nucleotide diversity, star‐shaped networks and significant results in neutrality tests indicate A. sculptum population expansions in some areas. Rickettsia amblyommatis , Candidatus R ickettsia andeanae and Rickettsia felis were detected. The A. sculptum diversity is not geographically, or biome delimited, pointing to a different potential in vector capacity, possibly associated with differing tick genetic profiles.