diff --git a/CHANGELOG.md b/CHANGELOG.md
index e8e4b015..3ef7c55c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,7 @@
 - Added `rmsd` and `rmsd_kabsch` to calculate RMSD without and with rotational alignment to `Structure` class (#230). 
 - Added `calc_rotational_constants` to calculate molecular rotational constants to `Structure` class (#230).
 - Added `calc_rotor_type` to classify a molecule's rotor type to `Structure` class (#230).
+- Add type checks for ncores and memory setters in `Input` and checks for invalid negative values (#261).
 
 ### Changed
 - Refactored methods from Runner into BaseRunner (#193)
diff --git a/src/opi/input/core.py b/src/opi/input/core.py
index 188519c3..fa238c80 100644
--- a/src/opi/input/core.py
+++ b/src/opi/input/core.py
@@ -114,12 +114,25 @@ def ncores(self) -> int | None:
     @ncores.setter
     def ncores(self, value: int | None) -> None:
         """
+        Setter for the ncores property. Value given must be a non-negative integer.
+
         Parameters
         ----------
         value : int | None
+
+        Raises
+        ------
+        TypeError
+            If the given value is not an integer.
+
+        ValueError
+            If the given value is negative.
         """
-        if value is not None and value < 0:
-            raise ValueError(f"{self.__class__.__name__}.ncores must be a positive integer.")
+        if value is not None:
+            if not isinstance(value, int):
+                raise TypeError(f"{self.__class__.__name__}.ncores must be an integer.")
+            elif value < 0:
+                raise ValueError(f"{self.__class__.__name__}.ncores must be a positive integer.")
         # << END OF IF
         self._ncores = value
 
@@ -130,12 +143,25 @@ def memory(self) -> int | None:
     @memory.setter
     def memory(self, value: int | None) -> None:
         """
+        Setter for the memory property. Value given must be a non-negative integer.
+
         Parameters
         ----------
         value : int | None
+
+        Raises
+        ------
+        TypeError
+            If the given value is not an integer.
+
+        ValueError
+            If the given value is negative.
         """
-        if value is not None and value < 0:
-            raise ValueError(f"{self.__class__.__name__}.memory must be a positive integer.")
+        if value is not None:
+            if not isinstance(value, int):
+                raise TypeError(f"{self.__class__.__name__}.memory must be an integer.")
+            elif value < 0:
+                raise ValueError(f"{self.__class__.__name__}.memory must be a positive integer.")
         # << END OF IF
         self._memory = value
 
diff --git a/tests/unit/test_input_core.py b/tests/unit/test_input_core.py
new file mode 100644
index 00000000..a97734ef
--- /dev/null
+++ b/tests/unit/test_input_core.py
@@ -0,0 +1,66 @@
+import pytest
+
+from opi.core import Calculator
+
+"""
+This module contains tests for the `ncores` and `memory` properties of the `Input` class.
+"""
+
+
+@pytest.fixture
+def empty_calc():
+    """An empty instance of `Calculator`."""
+    empty_calc = Calculator("test", version_check=False)
+    return empty_calc
+
+
+@pytest.mark.unit
+@pytest.mark.input
+@pytest.mark.parametrize("ncores", [0, 4, None])
+def test_ncores_valid(empty_calc: Calculator, ncores: int | None):
+    """Test for `Input.ncores` setter with valid values."""
+    empty_calc.input.ncores = ncores
+    assert empty_calc.input.ncores == ncores
+
+
+@pytest.mark.unit
+@pytest.mark.input
+@pytest.mark.parametrize("ncores", ["4", 4.0, [4]])
+def test_ncores_wrong_type(empty_calc: Calculator, ncores: object):
+    """Test for `Input.ncores` setter with values of the wrong type."""
+    with pytest.raises(TypeError):
+        empty_calc.input.ncores = ncores
+
+
+@pytest.mark.unit
+@pytest.mark.input
+def test_ncores_negative(empty_calc: Calculator):
+    """Test for `Input.ncores` setter with an invalid negative value."""
+    with pytest.raises(ValueError):
+        empty_calc.input.ncores = -1
+
+
+@pytest.mark.unit
+@pytest.mark.input
+@pytest.mark.parametrize("memory", [0, 4000, None])
+def test_memory_valid(empty_calc: Calculator, memory: int | None):
+    """Test for `Input.memory` setter with valid values."""
+    empty_calc.input.memory = memory
+    assert empty_calc.input.memory == memory
+
+
+@pytest.mark.unit
+@pytest.mark.input
+@pytest.mark.parametrize("memory", ["4000", 4000.0, [4000]])
+def test_memory_wrong_type(empty_calc: Calculator, memory: object):
+    """Test for `Input.memory` setter with values of the wrong type."""
+    with pytest.raises(TypeError):
+        empty_calc.input.memory = memory
+
+
+@pytest.mark.unit
+@pytest.mark.input
+def test_memory_negative(empty_calc: Calculator):
+    """Test for `Input.memory` setter with an invalid negative value."""
+    with pytest.raises(ValueError):
+        empty_calc.input.memory = -1