The Biological Examination Section was the last section to be established within the forensic laboratory. Even though the chemical laboratory was in charge of the few biological examinations performed during the initial period of more than 20 years, and even though the biological laboratory's beginnings were modest, with only one employee in 1971, 50 years later, this section has the highest workload and its DNA tests help solve the most serious criminal offences in the country.

The section is tasked with the identification of the physiological origin of biological traces and with genetic examinations. Until 2018 the section also performed morphological comparisons of hair fibres, and human and animal hair, whereas, now, examinations of this kind are carried out at the Physical Examination Section. For several years, the section kept and maintained a record of DNA examinations (a task now performed by an employee of the laboratory's management). In accordance with the requirements of the Prüm Treaty, this section also acts as the national contact point for the exchange of DNA profiles between signatories. At the moment, Slovenia exchanges data with 23 Member States.

Examinations of the Biological Examination Section:

• Preliminary examinations to establish the type of biological trace: chemical methods such as colour tests are used to indirectly identify whether the trace is blood, seminal fluid or saliva, whereby it is possible to establish whether the blood trace comes from menstrual blood. These are sensitive methods that are not completely specific and therefore can give false positive results.

• Immunochromatographic tests to establish the type of biological trace are confirmatory methods to establish the presence of blood, seminal fluid or saliva in the sample.

• The identification of human bodily fluids with biomarkers of the messenger RNA: mRNA (messenger RNA) biomarkers are used to identify vaginal discharge, menstrual blood or saliva.

• Standard examinations of nuclear DNA or STR typing of loci and a part of the amelogenin gene determine the sex and the identity of the person from the sample. It is also used to perform paternity tests and establish other family relationships. For all of the above-mentioned examinations (except for determining sex), comparison samples of suspects, injured parties and alleged relatives are required.

• Nuclear DNA examination of samples with degraded DNA (old samples, mishandling, traces on dirty surfaces) with inhibition entails mini-STR testing, while the typing of the amelogenin gene is conducted as it would be with standard typification. The purpose and requirements of this examination are the same as those of standard typification.

• Nuclear DNA examination of samples with minute amounts of DNA (samples of human DNA in minute amounts or samples of the DNA material of more than one person) - the procedures and purpose are the same as with standard nuclear DNA examinations and nuclear DNA examinations of samples with degraded DNA.

• The examination of male DNA consists of the DNA typification of loci on the Y chromosome. With this examination, the Y-chromosome STR haplotype in the sample is determined and, based on the comparison sample, haplotype matches are identified. The method is not individually specific and is used, under some conditions, for the identification of kinship thorough the male line when only distant relatives are available and for the identification of minute amounts of male biological traces.

• Data processing in the database of DNA examinations: the entry, search for and linking of matching STR profiles between persons and traces in the DNA database; for investigating suspects in criminal offences or linking criminal offences, and ensuring the eligibility of DNA data retention in the DNA database.