We present source catalogs for the 4 Ms Chandra Deep Field-South (CDF-S), which is the deepest Chandra survey to date and covers an area of 464.5 arcmin 2. We provide a main Chandra source catalog, which contains 740 X-ray sources that are detected with wavdetect at a false-positive probability threshold of 10− 5 in at least one of three X-ray bands (0.5–8 keV, full band; 0.5–2 keV, soft band; and 2–8 keV, hard band) and also satisfy a binomial-probability source-selection criterion of P< 0.004 (ie, the probability of sources not being real is less than 0.004); this approach is designed to maximize the number of reliable sources detected. A total of 300 main-catalog sources are new compared to the previous 2 Ms CDF-S main-catalog sources. We determine X-ray source positions using centroid and matched-filter techniques and obtain a median positional uncertainty of≈ 0 farcs 42. We also provide a supplementary catalog, which consists of 36 sources that are detected with wavdetect at a false-positive probability threshold of 10− 5, satisfy the condition of 0.004< P< 0.1, and have an optical counterpart with R< 24. Multiwavelength identifications, basic optical/infrared/radio photometry, and spectroscopic/photometric redshifts are provided for the X-ray sources in the main and supplementary catalogs. Seven hundred sixteen (≈ 97%) of the 740 main-catalog sources have multiwavelength counterparts, with 673 (≈ 94% of 716) having either spectroscopic or photometric redshifts. The 740 main-catalog sources span broad ranges of full-band flux and 0.5–8 keV luminosity; the 300 new main-catalog sources span similar ranges although they tend to be systematically lower. Basic analyses of the X-ray and multiwavelength properties of the sources indicate that> 75% of the main-catalog sources are active galactic nuclei (AGNs); of the 300 new main-catalog sources, about 35% are likely normal and starburst galaxies, reflecting the rise of normal and starburst galaxies at the very faint flux levels uniquely accessible to the 4 Ms CDF-S. Near the center of the 4 Ms CDF-S (ie, within an off-axis angle of 3'), the observed AGN and galaxy source densities have reached 9800+ 1300− 1100 deg− 2 and 6900+ 1100− 900 deg− 2, respectively. Simulations show that our main catalog is highly reliable and is reasonably complete. The mean backgrounds (corrected for vignetting and exposure-time variations) are 0.063 and 0.178 counts Ms− 1 pixel− 1 (for a pixel size of 0 farcs 492) for the soft and hard bands, respectively; the majority of the pixels have zero background counts. The 4 Ms CDF-S reaches on-axis flux limits of≈ 3.2× 10− 17, 9.1× 10− 18, and 5.5× 10− 17 erg cm− 2 s− 1 for the full, soft, and hard bands, respectively. An increase in the CDF-S exposure time by a factor of≈ 2–2.5 would provide further significant gains and probe key unexplored discovery space.