Yield and quality of flue-cured tobacco (Nicotiana tabacum L.) are often reduced by (NH₄)₂SO₄ on acid soils. Urea is a less acid-forming source of ammonium than (NH₄)₂SO₄ and may be a better source of plant nitrogen than (NH₄)₂SO₄ under acid soil conditions. Our objective was to determine the effects of soil pH, N source, and Cl^- on the growth, N recovery, and N use efficiency of flue-cured tobacco under greenhouse conditions. In one experiment, 300 mg N kg^-1 from four N sources [NaNO₃, (NH₂)₂CO, (NH₄)₂SO₄, and NH₄Cl] were added to a loamy sand soil (Typic Paleudult) at three pH levels (5, 7, and 9). ¹⁵N-labeled N sources were used on three replications and nonlabeled sources were applied to six replications. In another experiment, the nonlabeled N sources were added to the soil at two pH levels (5 and 7) and Cl^- levels of all sources were brought to the level applied with NH₄CI (760 mg kg^-1) using KCI. In both studies, one tobacco plant (‘Speight G-28’) was transplanted into each container. Nitrapyrin at 1 mg a.i. kg^-1 was applied to all treatments. Height, leaf number, and plant weight were highest for (NH₂)₂CO and NaNO₃ at pH 5, for (NH₄)₂SO₄ and NaNO₃ at pH 7, and for NaNO₃ at pH 9. Production of hydroxyl ions from the hydrolysis of (NH₂)₂CO may have countered acidity at pH 5 and improved its performance compared to (NH₄)₂SO₄. At pH 7, the acidic nature of (NH₄)₂SO₄ was countered by the higher soil basicity resulting in acceptable performance by this source. All NH₄⁺ sources were inferior to NaNO₃ at pH 9, probably due to NH₃ volatilization and toxicity. Tissue N concentrations generally were inversely related to dry weight, but N use efficiency increased from 17.0 g leaf g^-1 N for (NH₂)₂CO and NaNO₃ at pH 5 to 27.2 g leaf g^-1 N for (NH₄)₂SO₄ and NaNO₃ at pH 7. Apparent N recovery averaged 74% for NaNO₃ across all pH levels, but averaged only 54%, 41%, and 34% for ((NH₄)₂SO₄, (NH₂)₂CO, and NH₄Cl, respectively. Chloride concentrations in leaves were above 8% for all sources at pH 5 when a constant rate of Cl^- was applied. This resulted in no toxicity symptoms for NaNO₃, slight symptoms for (NH₂)₂CO, and severe symptoms for (NH₄)₂SO₄ and NH₄CI. Chloride levels were lower at pH 7, resulting in no symptoms for NaNO₃ or (NH₂)₂CO and only slight symptoms for (NH₄)₂SO₄ and NH₄Cl. NaNO₃ was the best N source across all pH levels in this greenhouse study. However, the study suggests (NH₂)₂CO may be an acceptable N source for tobacco under acid soil conditions while (NH₄)₂SO₄ may suffice at soil pH near neutrality.