Objectives: Long-term exposure to the human papillomavirus (HPV) is a known cause of squamous intraepithelial lesions that lead to cervical cancer. The loop electrosurgical excision procedure (LEEP) conization is an established treatment method. According to the latest recommendations, we present a paper to evaluate the effectiveness of various diagnostic methods of squamous intraepithelial lesions. Material and methods: We analyzed 229 patients who reported to District Public Hospital in Poznan to undergo LEEP conization in 2019–2021 during the SARS-CoV-2 Pandemic. The analysis included Pap smear/liquid-based cytology, HPV genotyping, colposcopy with targeted biopsy and LEEP-conization. We offered post-treatment HPV vaccination and, as a follow-up, performed HPV re-genotyping after six months. Results: In total, 89.1% of patients were HPV-positive. The coloscopy-directed biopsy (CDB) results show that almost 70% of the patients had high-grade intraepithelial lesions (HSIL). The diagnosis obtained by LEEP-conization showed that half of the women were diagnosed with HSIL and one-third with the low-grade squamous intraepithelial lesion (LSIL). The sensitivity of Pap smear/LBC accounted for 93.7% and was lower than for CDB, which reached 95.1%. Both diagnostic methods tend to underestimate the final diagnosis. Conclusions: The inclusion of a colposcopic examination in an in-depth diagnostic process in women with abnormal Pap smear results facilitates the identification of patients requiring therapeutic intervention. LEEP-conization may be used without the primary biopsy. It applies to multiparous women in the perimenopausal period, extensive abnormalities, discrepancies in test results, extensive visible abnormalities, and suspicion of invasive cervical cancer in the colposcopic examination.